Steroids and Hormones 1. INTRODUCTION Steroids form a group of structurally related compounds which are widely distributed in animals and plants. The name steroid is derived from the Greek word ‘stereos’ meaning solid. Steroids contain a characteristic tetracyclic carbon skeleton, the 1, 2-cyclopentenophenan- threne skeleton. 1, 2-Cyclopentenophenanthrene The steroids include sterols, the bile acids, the sex hormones, the adrenocortical hormones, certain sapogenins and some carcinogenic hydrocarbons. The steroids, particularly the bile acids, the sex hormones, and adrenocortical hormones, are responsible for a number of functions in human physiology and are of great biological importance. Cholesterol is the most important compound amongst steroids since all other steroids are derived from it. All steroids give among other products, Diels’ hydrocarbon, on dehydrogenation with selenium at 360°C. In fact, any compound which gives Diels’ hydrocarbon on distillation with selenium is onsidered to be a steroid. This aspect will be discused subsequently. 2. OCCURENCE Steroids occur in the plant and animal tissues. These are isolated by extraction of plant and animal tissues with organic solvents.Steroids and Hormone, 2 Concentration of the organic solvent yields lipids, which also contain steroids. The total concentrate Is sponified with alkali, ‘Th, nsaponifiable portion contains the teroids, which are purified by and column chromatography. crystallisation & 3. NOMENCLATURE The steroids are nomenelatured as per IL JPAC system. According to this system, the four rings of the skeleton are designated alphabetically, ic, as 4, B, Cand D. The numbering of the skeleton (1) isas shown below 29 P 1) Carbon numbering of steroidal-skeleton All steroids are given systematic names based on the parent steroidal skeletons, gonane, estrane and androstane (II, Il] and IV respectively). oy (HL) ree Estrane md, rostane (Vv) Pregnane Pregnane (V) j Position 17. Cholane seresented as ~ Cholan i androstane wi (VI) is also Tepresented a an ethyl group at ostane with sideSteroids and Hormones 3 chain at position 17 (X=CH; }. Other steroids like cholestane (VU). ergostane (VIII) and stigmastane (IX) are derived from cholane by changing the substituent X. x (vl) X= CHg c Cholestane (VII) X = CH,— CH zt Noy 7s Ergostane (VIII) X = CH—CH | Nery CHy CH. Stigmastane (IX) X = CH—CH < a | CH, CH, | CHy ng, the numbering When some of the carbon atoms in (I) are m mainder remains unchanged. When a methylene group is missing of the rer the prefix ‘nor’ preceded by the from the side chain, this is indicated by number of the carbon atom which has disappeared. In case contracted or enlars we use the prefixes “nor” or *homo* preceded by a small capital letter indicating the ring affected. The prefix ‘nor’ is also used to indicate the loss at an angular methyl group and, in this case, is preceded by the number designating that methyl group 18-nor and 19-nor. In case there is a ring fission with addition of a hydrogen atom to each new terminal group, this is indicated by the owing the position of the bond broken followed by the prefix ‘seco’, The prefix cyclo’ preceded by the numbers of the positions concerned, is used to indicate a three-membered ring. When more than one substituents are present in the same molecule, only one is indicated by suffix and the remainder as prefixes. The substituent to be selected by a suffix is given by the priority orderSteroids and Hormones > aldehyde > ketone > alcohol > amine > ys shown as prefixes. the location of the the lesser of the two acid > lactone > ester kyl and nitro groups are alway ted by the suffix ‘ene’; nd is specified by giving he double bond and then changing the terminal rbon to ‘ene’, In case the double bond is hich are not consecutively numbered, both numbers are given, the greater number being given in parenthesis. On the basis of these rules, the structures (X) and (XI) are named 6B, 17a-dihydroxyandrost-4-en-3-one and 5a-cholest-8(14)-en-3f-ol. oH Ceti7 i) 4 carboxyli ether. Halogens, and all Unsaturation is indicat carbon-carbon double bo numbers of the carbon in t «ane? in the parent hydrocat between two carbon atoms, W! OH (Xx) (xl) Some of the prefixes and suffixes are noted in Table 1. Table 1 : Prefixes and Suffixes. Suffix Olefinic double bond Triple bond an Acetat ne ie = Acetoxy yl acetate Benzoate an 2 Benzoylony yl benzoate pe Carboxylic acid eae a xylic aci m4 : id G3 ‘methyl ester Methoxy carbonyl es es : ny’ methy] oate Halogen as chloro a i. ae mino Given below - are the i addition of a CH; group Prefixes used in case there is omission or hydroxyl grou additional ring formati discussed” Table 2). Some of the es = Fa eet ave already beenSteroids and Hormones Table 2 : Special Prefixes. Modification of the group Nor Omission of a—CH- or other group. Homo Addition of a —CH- or other group. Cyclo Additional ring formed by means of a direct link between any two carbons of the steroid skeleton. Seco Fission of a ring with addition of a hydrogen atom at each terminus thus created, Anhydro | Loss of hydrogen and hydroxyl groups from adjacent carbon atoms with formation of a double bond. Loss of two hydrogen atoms from adjacent carbon atoms with formation of a double bond. Dehydro Deoxo Replacement of oxygen atom of a keto group by two hydrogen atoms. Deoxy Replacement of a hydroxyl group by hydrogen atoms. Dihydro Addition of two hydrogen atoms to a double bond. Some examples are given below, following the above noted rules : 23-nor-5-cholane Et H B-homo-5-pregnane 3,4-seco-Sa-cholane 4. CONFIGURATION OF SUBSTITUENTS The configuration of the substitutients is given by ‘a’ or ‘f’. In case the orientation of the substituent is above the plane of the ring (on the sameside as that of angular methyl groups at (C-10) and (C-13), the group h, the’ configuration. This is represented by a heavy full line bond. On as other hand, substituents below the plane of the ring have «y° configuration and are represented by a dotted line bond. A substituent whose configuration is unknown is represented by ~e’ and a wavy line bond. The configuration at a particular center in the skeleton is given in the correct Greek alphabet following the number of the carbon atom. An example is Sa, 148, 17a-pregnane. CHy—CH3 5a, 14a, 17a-pregnane The a and B configurations of the substituents are shown in the structure given above. 5. BASIC SKELETON The basic skeleton of steroids is a characteristic tetracyclic carbon skeleton, the perhydrocyclopentano-phenanthrene nucleus, which Is shown below : Perhydrocyclopentano- phenanthrene 6. DIELS’ HYDROCARBON As already stated, all steroids on dehydrogenation with selenium at 360°C give Diels’ hydrocarbon along with chrysene (Scheme 1.). Formation of chrysene takes place because of the fact that the angular methy! group at C-13 enters the five membered ring D forming 4 six numbered ring.Steroids and Hormones i CHg3 mse + 360°C ” CI COO SS Cholesterol Chrysene (Scheme 1) Diels’ hydrocarbon is a solid, m.p. 126-127°C. Its molecular formula, as determined by usual methods, is found to be Cg Hyg. On the basis of X-ray crystal analysis and absorption spectra, Diels’ hydrocarbon is shown to be 3'-methyl-1,2-cyclopentenophenanthrene. This structure was established on the basis of the synthesis of the compound (Scheme 2). CH 2 CH,MgBr OH " i a 0. | + — S HC 2-(1-naphthyl)-ethy! 2, 5-Dimethyl- magnesium bromide cyclopantanone CH; CHg H P2Os, sae _ “so, Distil. Distil. under CH aa Cl re Contd.Steroids and Hormon, es CH3 Diels’ hydrocarbon (Scheme 2) 7, STEREOCHEMISTRY The stereochemistry of steroids deals with (i) Configuration of substituents (ii) Configuration of the side chain (iii) Conformation The configuration of the substituents has already been dealt in section 4. Configuration of the Side Chain In accordance with the earlier tradition of assigning a and feconfigurations to steroids (section 4), the configuration at C-20, the term a- and are used as shown in the Fig. (XI) below, when there are two carbon substituents at C-17. (xl) - fee Current practice, the sequence rules of ‘RS’ nomenclature peer eae the stereochemistry at C-20 and other positions in the chain longer than ethyl. In case of cardenolides, the figuration at C-20 is *20R’, when the lactone ring is saturated. Conformation This as; i pes a a with the way in which different rings in steroids BK - In a completely saturated steroid system, rings 4, 8Steroids and Hormones 9 po Cac aoe rings and the ring D is a cyclopentane ring. It is - at a cyclohexane ring preferabl ir than a boat conformation. ee na LF AT AN Chair Boat Chair Conformations of cyclohexane When two cyclohexane rings are fused (as in the case of rings 4 and B or B and C in steroids), the fusion can take place in two different ways. In one mode, the two substituents in the ring junction are oriented in opposite direction and are said to be ‘trans’ to each other. In the other mode, the two substituents at the ring junction are said to be ‘cis’ to each other. In the former case, the two cyclohexane rings are ‘trans fused’, and is the second case, the two cyclohexane rings are ‘cis fused’. These two cases are represented as follows : H trans fusion cis fusion Conformation of 4/B rings The rings 4 and Bin steroids can be either cis or trans fused. In either case, the variation in stereochemistry at C-S rather than at other centres 1s more important. Saturated steroids like cholesterol are 4 / B-trans or Sa compounds. However, the bile acids are 4/B-cis or 5B compounds. Earlier, the term ‘allo’ was used to indicate Sa-configuration. Conformation of B/C rings On the basis of X-ray crystallographic studies (Bemal and coworkers) it has been shown that in majority of the steroids, the B/C ring BIC ring junction gives conformational junction is mrans. The frans ring 4 is expected to be conformationally stability to 5B steroids, w here mobile due to 4/B cis junction. Conformation of C/D rings In sterols, bile acids and related compounds, the C/D ring junction is mans. However, in cardiac glycosides, the CID ring junction is cis-fused. The fusion of the four rings (as shown in structure XII) confers certain rigidity to the steroid structure. This structural rigidity10 Steroids ang Horm, Ones differentiates axial and equatorial positions, which are important i, ti chemical reactions. H (xi!) Fusion of A, B, C and D rings in steroids (A/B = trans, B/C = trans, C/D = trans) On examination of the fully saturated structure of a sterol, we fing that there are eight eee centres in the molecule (3, 5, 8, 9, 10, 13, 14 and 17). Thus, there are 28 =256 possible optical isomers. In case we also include the chiral centre in the side chain (i.e., carbon-20), then there are 512 possible optical isomers. In the nucleus, there are six chiral centres (5, 8, 9, 10, 13 and 14) and so there are 2° = 64 theoretically possible optically active forms. However, in practice many of these cannot exist due to steric interactions.9. STEROLS There are 3-monohydroxy steroids, They are crystalline compounds ang occur free or as esters of higher fatty acids. These are isolated from the unsaponifiable portion of oils and fats. Depending on their occurrence, the sterols are normally classified as follows : Q Zoosterols : These are obtained from animal sources, Examples include 5a-cholestan-3p-ol (cholestanol) and 5B-cholestan -38-o] (coprostanol). Q Phytosterols : These are obtained from plants. Examples include ergosterol and stigmasterol. Q > Mycosterols : These are found to occur in fungi and yeast. Example includes mycosterol. Q Marine sterols : These are obtained from marine organisms. The above classification is only tentative. There are, however, certain sterols like ergosterol, which occurs both in plants and animals, 9.1. Colour Reactions of Sterols Sterols give a number of colour reactions. These colour reactions are useful for preliminary identifi using colourimetry. Some of the below : (i) Salkowski Reaction ; A ¢| treatment with conc, chloroform layer. (ii) Liebermann Burchard Reaction: chloroform solution of cholesterol with si acetic anhydride gives q greenish colour. (iii) Rosenheim test : Treatment of a chloroform solution of ster! with 90% trichloroacetic acid gives blue or pink colour. cation and for quantitative analysis colour reactions of sterols are given hloroform solution of cholesterol on Sulphuric acid gives a red colour in the Treatment of @ ulphuric acid andSteroids and Hormones 15 (iv) Fieser test : The sterol on treatment with selenium dioxide in benzene at 20°C gives a yellow colour for Sa series. Sterols. with 5B series do not give any colour. (v) Lifschutz test : A mixture of sterol and perbenzoic acid is heated in glacial acetic acid. Addition of conc. sulphuric acid tc the hot solution gives an intense blue or green colour. (vi) Zlatkis test : To a solution of ferric chloride in concentrated sulphuric acid and glacial acetic acid is added a solution of cholesterol in glacial acetic acid. A purple colour appears. This test is used for the determination of cholesterol in plasma The following sections deal with the structures of cholesterol, Janosterol, ergosterol, Vitamin D and stigmasterol. 9.2. Cholesterol Cholesterol is the chief constituent of gall stones (99%) and is also present in human brain. About 200 g cholesterol is present in an average adult human. It is always found in vertebrates, often in invertebrates but rarely in plants, and is present in the free state as well as esterified form. 9.2.1. Isolation Chloroesterol is isolated on a industrial scale from th and brain of cattles. It is obtained by extraction with solvent and purified by crystallisation of its 5,6-dibromo derivative. Debromination is then affected by treatment with zinc and acetic acid or with sodium iodide and ethanol. spinal cord 9.2.2. Structure Determination of Cholesterol The molecular formula of cholesterol, as determined by usual methods, is found to be C27 Has O(m-p., 149°C). The structure of cholesterol was determined by the work of Wieland, Windus and their coworkers (1903-1932). On acetylation, cholesterol gave a monoacetate indicating the presence of a hydroxyl group. The hydroxyl group was found to be secondary one, since on oxidation it gave a ketone (cholestenone). The presence ofadouble bond - in cholesterol was shown by its bromination into a dibromide Also on reduction, cholesterol gave @ dihydro compound (cholestanol) confirming the presence of a double bond. All these reactions are given in Scheme 3, in support of the structure of cholesterol.11. HORMONES Hormones are excreted by the ductless glands. Only minute amounts of hormones are required to produce various physiological effects in the body. The deficiency of a hormone leads to a particular disease. which can be cured by the administration of that hormone. More than fifty hormones have been characterized and out of these about thirty are steroids and the rest are non-steroid hormones. The steroid hormones are of two types. These are sex hormones (female and male) and the adrenal cortical hormones. Also, there are two kinds of female sex hormones— estrogens and gestogens. The above classification of hormones 's represented below in a summarized form. Hormones Steroidal hormones Non-steroid hormones Sex-hormones Adrenal cortical hormones ] Oestrogens l : Gestrogens (follicular hormones) (corpus luteum ho Andogens (female sex hormones) rmones) (rnale sex hormones!er0ids and Hormones 63 14. sex-Hormones The sex hormones belong to the steroid class of com; roduced in the gonads (testes in the male and ovaries in ies othe activity of the sex hormones is controlled by the hormones thy os roduced in the anterior lobe of the pituitary gland. os tha ae As already stated, sex-hormones are of three types. These are : which include oestrogen, oestradiol and ee the important member being progesterone and which include androsterone and testosterone. @ oestrogenes, (i gestogens, (ii) androgens, 41.1.1. Oestrogens or Follicular Hormones Oestrogens (oestrogens) are a group of sex hormones and are characterized by their ability to produce heat (estrus) in females of various mammalian species. The estrogens are produced mainly in the ovaries. Subsequently, these pass on to the uterus and vagina and are responsible for causing characteristic changes in the epithelial tissues of the vagina during the uterine cycle. Three main estrogens, Vi2.. estrone, estradiol and estriol are the main members of the family. The ovary produces mainly estradiol. The estrogens were the isolated (estrone from human preganc: Doisy in 1929). first steroidal hormones which were yy urine of pregnant women by R R RA R’ _ Estrone =0 H Estradiol OH H Estriol OH --OH HO" 11.1.1.1. Estrone (Oestrone) Estrone was isolated by Butenandt e estrogens are presen! Doisy independently from 2 of and tin the urin the urin e of pregnant women. Th an pas and humans as the glucuronides. These are converted into the por orm by hydrolysis with hydrochloric acid Followed by exation Patttion between organic. solvents t0 give Ne miXtUT tic -erorm (estrone) was PUTT We ketoni frm estrone) MP ving (c heceens). From this mixture, t sta gsonuble semicarbazone d ind the non-ketonic products (Sc! jerivative (Girard der heme 47)-11.1.3 Androgens or Male Sex Hormones The androgens are also called male hormones. These are c-19 steroids. The main naturally occurring androgens are androsterone, dehydroepiandrosterone and testosterone. 11.1.3.1. Androsterone Androsterone was isolated by Butenandi et al (1931) from male urine, in which it is present to the extent of about 15 mej 15,000 litres of urine. Its structure is based on the following i 8 n about 15, oints :and Hormones: 95 The molecular formula of androsterone, as deter usual methods, is C19 H39 0, It contains one hydroxyl group, since it forms mono-esters. mined by 4 a contains one keto group, since it forms a mono-oxime. This accounts for both the oxygen atoms of androsterone. 4, Androsterone is a tetracydic compound. The parent hydrocarbon of androsterone is C}yH39 which corresponds to the general formula C,,H>,,_. So, the molecule is tetracydic 30 2 (D.B.E. of CjgH3902 =19+1-— =5; it includes 1 double bond of C=O group and so there are four rings), On the basis of the above, it was believed that androsterone bly contains the steroid nucleus and is an hydroxy ketone. Butenandt (1932) proposed a structure for androsterone, which was found to be correct by Ruzicka (1934) on the basis of the following facts : Ruzicka oxidised Sa-cholestany! 3f-acetate with chromium mnoxide in acetic acid and obtained epiandrosterone (Scheme 76). Infact, Butensndt proposed this structure for androsterone, which was found to oxidised, Sa-cholestanyl be untenable. However, when Ruzic! Avacetate, the product obtained was androstenone (Scheme 76). op’ = ~ 1.C10s YN ty 2 Hydrolysis H AL Ww $= Cnsnetan facta , 4 l a] | ANE | | H H A Ae HO 4 Epiandrosterone Contd.Steroids and Hormenes 1.0103 2. Hydrolysis H 5a-Cholestany! 3a-acetate Androsterone (Scheme 76) In androsterone, the configuration of the hydroxyl group at C-3 is a- and not B- as was suggested by Butenandt. Epiandrosterone, obtained above (Scheme 76) by oxidation of Sa-cholestanyl 3B-acetate, was converted into androesterone by using the following sequence of reactions (Sondhamer et al 1955) (Scheme 77). Epiandrosterone ——» ! Contdsteroids and Hormones r~OH ‘'—OH Androsterone — - O_ Lo oO. Lo o™ LiAIHy H cae H I aaeeae Hj] H i HO” fi H H (Scheme 77) A convenient preparation of androsterone starting with dehydro- epiandrosterone (Caglioti et al, 1964) is given below (Scheme 78) OH Con ——— TsOH, PhH Dehydroepiandrosterone Oppenauer oxidation Contd, alSteroids ang Hormon, es --OH '—OH ——_—_> TsOH, PhH 1. ByHg 4s, 2. H,0,/0H™ 3.H* Ho™ Androsterone (Scheme 78)11.1.4. Adrenal Cortical Hormones i i ese The adrenal gland (located over the kidney) has er ee are : (i) medulla (the inner region), which produces a Grenocortica (ii) cortex (the outer region), which produces the a ied by hormones or corticoids. The production of corticoids is controls val hormone produced in the anterior lobe of the Pituitary, the ° for adrenocorticotrophic hormone (ACTH). The corticoids are kn the : : ctions various physiological functions, However, their main ace the include the control of carbohydrate, and protein metabolism, an' control of the balance of water and electrolytes. tract of A large number of Substances were isolated from the eX ounds adrenal cortox, Girard's Teagent was used to separate the keto comp from the non- : was keto compounds, Subsequently, each fractio" fo! Separated by adsorption or Partition chromatography. As manyer a steroids and Hormones 103 steroids were isolated by different workers. These substances were originally designated by letters (different workers using different letters for the same compound), but many are known by trivial names. It is believed that eight of these substances are highly physiologically active. ‘The structures of these active substances are given below : a gHeoH | Substance Q; Substance H; 11-Deoxycorticosterone; Corticosterone; 12-Hydroxyprogesterone; 11, 21-Dihydroxy- Cortexone progesterone CH,OH GHOH Substance S; 11-Deoxy-17-hydroxy- corticosterone; Cortexolone 21CH20H Compound A; 11-Dehydrocorticosterone; 21-Hydroxy-11-keto- progesterone 4 Substance M; Substance F; f 17-Hydroxy- Compound E; corticosterone; 11-Dehydro-17-hydroxy- Cortisol corticosterone; Cortisone Contd.HR 10” ~ is ° Sneaneec Aldosterone The corticoids are strong. reducing agents; this is due to the presence of an a-hydroxy ketone group 11 the molecule The hydroxy) group at position 12 behaves in the usual way. However, the keto group does not form an oxime or a phenylhydrazone (possibly due to steric hinderance). Also, the 1 l-keto group is resistant to catalytic reduction in neutral solution, but can be reduced in acidic solution. Lithium aluminium hydride reduces the 11-keto group to a hydroxy! group. By Clemmensen reduction, the 1 1-keto group is reduced to CH) group. The structure elucidation of corticoids has been achieved by degradation and their partial synthesis from steroids of known structures, Synthesis of deoxycorticosterone from stigmasterol is an example (Reichstein et al, 1937, 1940). The first step of this synthesis involves the conversion of stigmasterol into pregnenolone (Scheme 69). The subsequent steps are given below in Scheme 83. CH3 I co Cros coe id. Conter greroids andl Hormones 1 COCHNe Le H | Oppenauer SEN oxidation” H GH,OH Dooxycorticostorona (Scheme 83) The structure elucidation of cortisone, cortisol and aldosterone will be dealt with in the following sections, 11.1.4.1. Cortisone Cortisone (Substance F or Compound £2) is used in the treatment of rheumatoid arthritis and rheumatic fever. Its structure 1s determined as follows : The molecular formula of cortisone is C2 Ha9Os It cont a, B-unsaturated group since itis very sen tive to alkali, Usual the presence of one double bond, two ketonic groups, one primary alcoholic and one tertiary alcoholic group. It contains a a-keto group (-CO.CHOH), since it reduces alkaline silver nitrate and Febling solution. Oxidation of cortisone with chromic acid gives adrenosterone. Both adrenosterone and cortisone were ound to contain ketonic group at position 3. In fact, both were ar, Punsaturated ketones: as found by comparison of their UV absorption spectra with that of other steroid hormones like testosterone and progesterone. So, the double bond was found to be present between positions 4 ‘and 5. Hydrogenation of adrenosterone gives a triketone of known tructure (mp., 178°C), which was found to be a derivative of 3,17-diketone. “This is further confirmed by the formation of andostane by reduction of the triketone first by Clemmensen reduction and then by hydrogen: rhus, cortisone is rel to andostane. Oxidation of cortisone with periodic acid giv \7-hydroxy acid, which proves the presence of the second hydroxyl group. All the above transformations can be explained by assuming (1) as the structure of cortisone (Scheme 84). ins an how106 Steroids ang Hor Mon, a . Cortisone [i104 17-Hydroxy acid Triketone (m.p., 178°C) 1. Zn-Hg HCI (Clemmensen redn.) 2. Hp Andostane (Scheme 84) The structure of cortisone was then confi synthesis starting from 30,21-diacetoxypre, _ 1948) (Scheme 85). gnane. irmed_by its partial 11,20-dione (Sarett.and Hormones grerords, 107 CH,OAc i ons ss HEN 3a. 21-Diacetoxy pregnane-1 1, 20-dione CH;,0Ac 2. KOH CH;OAc | CCN Os04 te Contd.108 1. -HBr Seay RUPEE al 2. Hydrolysis Cortisone (Scheme a5) A number of total s various workers. One hi; en by the 'yntheses of cortisone have been oi 9m) is ighly sterospecific synthesis (Sarett et al, en used leme 86. The scripts 4, B, C and D have be' antares {0 diesignate the specific Tings. In this synthesis, 3-ethoxyPe ne i" quind! 3-diene (1) was Subjected to Diels-Alder reaction with p-benz0' (I) to give the cis fused ; enatio® diketone (111), Selective catalytic hye ii Of (III) then gave the diketone (IV), which on reduction wiSteroids and Hormones 109 aluminium hydride formed the diol (V). Acid hydrolysis of (V) gave (VI), which on Michael condensation with methyl vinyl ketone in presence of alkali (Tricon B; Me3NCH)Ph*OH™ ) followed by cyclisation gave the tricyclic ketone (VII) carrying a B-methyl group. The keto group in (VII) was protected by conversion into a ketal (VII) and the ketal subjected to Oppenauer oxidation to give (IX). (IX) is formed with inversion to give the more stable ¢rans-fused rings. (IX) was then converted into cortisone acetate by the sequence of reactions as shown in Scheme 86. O. 0 Cs reaction ZA O° Eto w a) (tl) cis adduct Ho-Ni O LAH oH seine _— elective redn. Eto Ee Vv) vy g HO, HO, Cs) i ‘OH oD H,0* On 2, Ce He. oO OH on vi c HO, on G OH Oppenaver, ao, 0. oxidation H iv (vil) Contd.Steroids and Hormones 110 Hon Arpi*o 4. Mel; Bu'OK 2. CH,=CMeCH,I; Bu'OK Ot AY ~) aX H,CMe=CH, OAH H CsHsN °O. »CH,CMe=CH, 0 (xD) CH,CMe=CH, HCI a (+H20) “C=COEt OH OAL .CH,CMe=CH nCHjCMe=CH, [ay Pr Ronco ‘CHCO,Et ~N 0. CHjCMe=CH La 2 1-005 | NaBH, SIHI08 peste CHaCMe=CHe 'CH,CO,Me Contd.steroids and Hormones 114 scl, 'CH3CO,Me Cohen coMe come OTs ee (CO.Me), os paaeecs “Veoh * COCH;COCO,Me 1. NaOH — 2.H* 3. Resolution COCH,;COCO,H ° AcOK HO (CH20Ac COCH20Ac No. < PA ° °. CN HCN POC, BHIONTS CsHsN _GH2OAC cv 0. CN H KMnO, Fr Piperidine Cond.PIII sand 4, eaesnesessanenetiaieann Mig 2 ™ ie HMyOAG 0. hi OH (_ | " | MeO o | " 4 COC Op, \ 0 on Neo " \ {uf | { yii Cortisone acetate oO (Scheme 86) Many cortisteroidy have been produced Commercially by microbiological transformations, Hor example, progesterone is converted into cortisone by Rhizopus nigrans, Cortisone his been used in the treatment of rheumatoid arthritis and rheumatic fever, Besides the above, cortivone has also been used in curing Addison's disease, asthma and inflammatory eye dis 11.1.4.2. Cortisol ‘The structure of cortisol is similar to that of cortisone, with the only difference that there ix a OU group aC), instead of ketonie proup. It structure (given below) is clucidated in the same way as thal of cortisone ‘lacie co HO. J OH al “ H H Contisot ‘The structure ; Of Cortisol is co cortisone: nfirme 3 artings trom acetate (Scheme 87), hed by its synthesis startingSteroids and Hormones 113 COCH,0Ac OH HDN.NH.CONH,.HCI (Semicarbazide hydrochioride) aq. CH;OH— NaHCO, No, 3.5 hrs. Cortisone acetate CH,0Ac .NHCONH,.HCI IH KBH, ——— THF HCI.NH2.CO.NH.N Bis-semicarbazone aia C=N.NH.CO.NH2.HCI OH HCI.NH2.CO.NH.N HCI Excess NaNO3 Cortisol (Scheme 87)11.1.5. Non-steroid Hormones 11.1.5.1. Adrenaline Adrenaline is a non-steroid hormone and was obtained from the medulla part of adrenal gland, which contains adrenaline as well as nor-adrenaline. The main function of adrenaline is to increase the blood pressure. It is also used locally to stop haemorrhage. Adrenaline is a crystalline solid (m.p., 211°) and is soluble in acids and alkalies. It is also optically active, [a]p —535° Its structure is established as follows : The molecular formula of adrenaline is Cg H) 3 NO3. It dissolves in sodium hydroxide and is reprecipitated from the solution by passing CO}. So, it contains a phenolic hydroxyl group. Adrenaline is found to be acatechol derivative, since it gives a green ferric reaction. Adrenaline on heating with aqueous KOH gives methylamine. Thus, most likely a methylamino group is present in adrenaline. On fusion with KOH, adrenaline gives protocatechuic acid (Takamine, 1901), However, if the methyl ether of adrenaline is fused with KOH, veratric acid and trimethylamine are obtained (Jowett, 1904). The above transformations are shown in Scheme 89.! Steroids A A» CHgNH2 Adrenaline —q°KOH — Methylamine | OH OH KOH fusion Methylation ont Protocatechuic acid OCH3 OCH, Methyl ether KOH tsion, + (CHgN Trimethy! amine COH Veratric acid (Scheme 89) Formation of trimethylamine (Scheme 89) indicates that the 1V atom must occur at the end of the side chain. As already stated, adrenaline is optically active; so, it must contain at least one chiral centre. Besides two phenolic hydroxyl group (catechol unit), it contains a secondary alcoholic group. The presence of secondary alcoholic group is indicated by the fact that treatment of adrenaline with benzene sulphony] chloride followed by oxidation of the tribenzenesulphony! derivative gives @ ketone (Friedmann, 1906). In order to account for the oxidation of adrenaline ' protocatechuic acid and vetratric acid (Scheme 89), it is believed that the -CHOH- group must be directly attached to the nucleus (CH CHOH group is expected to give a phenyl acetic acid derivative). On the basis the above evidences, adrenaline is given the structure (I) W hich was confirmed by its synthesis (Stolz, 1904; Dakin, 1905) (Scheme 90) OH OH OH OH HN + CICH,CO,H POC os Chloro acetic acid Catechol COCH,CI -Chloro-3, 4-di- hydroxyacetophenone contdsteroids and Hormones 119 OH OH OH KOH —_ Z COCH,NHCH3 CHOHCH,NHCH, ) (+)-Adrenaline (Scheme 90) The racemic adrenaline thus obtained (Scheme 90) is resolved by means of (+)-tartaric acid. 11.1.5.2, Noradrenaline Noradrenaline is present along with adrenaline in adrenal medulla. The natural compound is laevorotarory and is the most powerful pressor-compound known. The structure of noradrenaline (C}g Hj NO ) is established in the same way as in the case of adrenaline. Finally, the structure of hormone is confirmed by is synthesis (Scheme 91). OH OH OH OH OH OH HCN Na EtOH CHO CH(OH)CN CHOHCH,NH2 Protocatechuic Cyanohydrin (#)-Noradrenaline aldehyde (Scheme 91) 11.1.5.3. Thyroxine (Thyroxin) Thyroxine, a non-steroid hormone, is an iodine derivative found in the protein thyroglobulin, which occurs in the thyroid gland. It was isolated by Kendall (1419) and Harington (1930) as a white crystalline solid [m.p. 235°, [a]p - 4-4]. Hydrolysis of the protein thyroglobulin yields the common amino acids along with thyroxine and the various iodinated derivatives, which include L-histidine (4-), L-tyrosine (3- and 3.5-) and L-thyronine. Thyroglobulin is found to contain three iodothyronines, viz.,3, 3:3, 3", 5'and 3, 3', 5. Of these, the last one shows the maximum biological activity. The structure of thyroxine was established as follows : formula of thyroxine was established as 1926). When thyroxine is treated with esence of colloidal palladium, the to form thyronine (thyronin), The molecular CisHyj14NOg (Harington, hydrogen in alkaline solution in pr iodine is replaced by hydrogenCisHisNO4. whi mtn Hin an on fusion win KON gquinol, oxalic acid and a compound co" of p-hydroxy! BH ) (Scheme 92). A structure (IL) proposed for thyronine wouiq Nie » ( (Sel these products. ax. alkaline solution, 5, > i Thyroxine —F,jcoliidal Pd Yronine (thyronin Cyst slaNOa _— CrsHieNo, s108 | yas yo We gooH H IH + + NH, wos . {a COOH . Pe Quinol Oxalic Ammonia benzoic acid ect KOH fusion 250°C prHydroxy-benzoie acid + Quinol + Compound (Ci3H,20,) (Scheme 92) HO { O { HaGH—COWH (i) NH Thyronine The compound (1) was also obtained by subjecting thyronine (provisional structure II) to exhaustive methylation followed by oxidation of the product formed. The following structure may thus be proposed for compound (I). ope pon Compound (I) (C1gH120.) The above structure for synthesis (Scheme 93). CH o Hl Ve + ro \-on, Taree P-Bromoanisole P-Cresol (Pot. salt) compound (1) was later confirmed by ContFP Steroids and Hormones 421 —> CHj0 O ll, ono \-o€ \-com ar (Scheme 93) The above results (Scheme 93) indicate that thyronine (II) molecule contains two benzene nuclei linked through an ether linkage (-C6H4-O-CH4-) Also, one of the nuclei carries a hydroxyl group at para position to the ether linkage. The side chain consists of a three carbon fragment. Thus, a partial structure of thyronine may be written as follows : Part structure of thyronine It is found that thyronine on heating with HI gives tyrosine and p-OH- CgHy—CH CH(NH )COOH. Thus, the structure of thyronine is as given below. HO C? oO > CHF HCOOH NH, Thyronine (II) The structure of throxine may now be arrived at by placing four iodine atoms on thyronine unit. The position of iodine atoms in throxine is established as follows : Fusion of thyroxine with potassium hydroxide gives two pyrogallol derivatives (this involves replacement of iodine atoms by ~OH groups). The formation of pyrogallol derivatives indicates that two iodine atoms are in ortho position to the original hydroxy! group in each benzene nucleus. Thus, thyroxine may be represented by assuming structure (III) as shown in Scheme 94. I I ~ _ KOH Fusion HON H2—CH—COOH ————_ > \ ION J Fj NH2 T I (If) Thyroxine Contd.Steroids and Horm, 122 = on i - H + HO ‘CHeCHCOOH > HO eo \ NH, OH OH Pyrogallol derivatives (Scheme 94) The structure (ID) for thyroxine is finally confirmed by jt jarington et al, 1927) (Scheme 95). synthesis (H I ~ | _— 1, NaNO,/HCI aoa ae pe on p/Nitroaniline S ono -on oH 0 —— K,COs in butanone woe No, 2S0CeHO! = 2. CgHy ;ONO-HCI I 1 opie Gun, 1 I orl \o yy __SaOl-HeI ~ Stephen reaction f . me cH SetSPONHOH-CON, ComeSteroids and Hormones 123 —> CH. of \ ° co- ° ° Heo’ HI ae P Azlactone 1 wot \-o~ _\-cteu CO, — L | Cone. NH3/H,0” I NHp I I Ho \ / etn NH I I 2 (#)-Thyroxine (Scheme 95) The racemic form of thyroxime obtained above (Scheme 95) was resolved via its formyl derivative (Harington, 1928). Subsequently (1934), it was shown that this amino acid belonged to L-scries. Given below are the three other hormones of the thyroid gland : I H>—CHCO3H HON Nl i a GHCO2 NHp 3, 3'-Di-iodothyronine I I wi yok oe | 2 3, 3', 5'-Tri-iodothyronine124 I 3, 3’, 5-Tri-iodothyronine Steroids and Hormones ao CH2CHCO2H 7 ee NH2