Advances in the stereoselective synthesis of antifungal agents and ...

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Chapter 1 17was synthesized by the Bayer AG in 1972 61 . It has been shown to have abroad spectrum of antimicrobial activity against dermatophytes, pathogenicyeasts, filamentous and dimorphic fungi, as well as against some grampositivebacteria. Studies have shown that 6d required only a very shortcontact time in order to achieve maximum inhibitory activity 62 Itsubstantially inhibits the uptake and intracellular pooling of leucine, lysineand other aminoacids in the absence of glucose 63 .Clotrimazole 6d was shown to be orally active in early in vivo studiesbut problems with toxicity and side effects directed the developmenttowards topic applications. The efficacy in the treatment of experimentalfungal infections decreases as a function of time 64 . A progressive decline inserum concentrations of the drug after administration over several days hasnot been observed. This means a high metabolic stability and a long halflife. Other problems following oral administration 65 are unacceptable highincidences of gastrointestinal disturbances, as well as hepatic and adrenalchanges.Clotrimazole 6d has been proven to be effective and safe in the topicaltreatment of a variety of fungal infections. It is as effective as hystatin in thetreatment of superficial Candida infections. Clotrimazole 6d has beenshown to be also active in the treatment of oral Candidiasis.1.3. Inhibitory activity of anticancer drugs on Aromatase.The biosynthesis of steroids occurs in the gonads where sexualsteroids are produced and in adrenals where glucocorticoids andmineralcorticoids are synthesized. However, extra glandular production ofsome steroids also takes place in peripheral tissues. For example,aromatase, which converts androgens into estrogens has been identified in awide variety of tissues.A number of clinical situations are documented in which steroidhormones, either in normal amounts or when produced in excess play arole in the pathogenesis of diseases. Thus, inhibiton of the steroidproducingenzymes is a valuable means of treating these conditions. Untilrecently, however, there were relatively few inhibitors available thatwere specific for any one steroidogenic enzyme. Most of thesecompounds inhibit steroid hydroxylation and interact with theCytochrome P-450 component of the enzymes.
Chapter 1 18In the last few years, several compounds have been identified thatselectively inhibit aromatase. Since estrogens are important in a variety ofphysiological processes and diseases such as gynaecomastia, precociouspuberty, and endometrial and breast cancer - the leading cause of deathamong women66 with approximately 40000 deaths per years in the U.S.A.alone 67 , selective inhibitors of aromatase are proving useful for bothinvestigational and therapeutic purposes 68 .Basic and clinical data suggest that human breast cancers can bedivided into hormone-dependent and hormone-independent subtypes, theformer accounting for one-third of the over 100,000 new cases diagnosed inthe USA each year, and even being more prevalent in postmenopausalwomen 69 . It was envisaged that an effective inhibition in the biosynthesisof estrogens may be useful for controlling the amount of circulatingestrogens and, consequently, of estrogen-dependent disorders 70,71 .1.3.1. The Enzyme Complex Aromatase.The aromatization of C19-steroids (androgens) on the way to C18-steroids (estrogens) constitutes the last and most important step in thebiosynthetic pathway from cholesterol to estrogens (Scheme 1.2). This isperformed by the enzyme complex aromatase (estrogen synthetase),consisting of a flavoprotein NADPH dependent-cytochrome P-450reductase that transfers electrons from NADPH (nicotinamide adeninedinucleotide) to the terminal enzyme, and a specific form of the cytochromeP-450 enzyme system, known as aromatase cytochrome P-450, which is theprotein involved in the specific recognition and binding of C-19 steroidsubstrates.It catalyzes the multistep oxidative reaction sequence leading toaromatization of the ring A of the steroid 72 . Aromatase, along with othersteroidogenic enzymes such as the cholesterol side-chain cleavage enzyme(desmolase), 21-hydroxylase, 11β-hydroxylase, 18-hydroxylase, 17αhydroxylase,and 17,20-lyase, form part of the subgroup of cytochromeP-450 enzymes.
Page 1 and 2: Advances in the stereoselectivesynt
Page 3: ACKNOWLEDGMENT:I would like to than
Page 6 and 7: Summary:Numerous drugs are chiral,
Page 8 and 9: IndexII2.2 Synthesis of enantiopure
Page 10 and 11: IndexIV4.4. Stereochemical Assignme
Page 12 and 13: IndexVImethyl amine 69 1446.6. Stud
Page 14 and 15: IndexVIII8.23.3.1 Desilylation usin
Page 16 and 17: Chapter 1 11.Introduction1.1. Chira
Page 18 and 19: Chapter 1 3The concept of stereoche
Page 20 and 21: Chapter 1 5switches is in the area
Page 22 and 23: Chapter 1 7-bonds 9 . It is now wid
Page 24 and 25: Chapter 1 914CH 3Cyt P-450 DMOH3O 2
Page 26 and 27: Chapter 1 11piperazine) is also the
Page 28 and 29: Chapter 1 13The four stereoisomers
Page 30 and 31: Chapter 1 15single enantiomers and
Page 34 and 35: Chapter 1 19HOHODesmolaseHOCholeste
Page 36 and 37: Chapter 1 21formic acid results in
Page 38 and 39: Chapter 1 23inactivation. 113 . Bec
Page 40 and 41: Chapter 1 25Two newer compounds whi
Page 42 and 43: Chapter 1 2715 is an advanced repre
Page 44 and 45: Chapter 1 29transformation of the a
Page 46 and 47: Chapter 1 31Enantioselective synthe
Page 48 and 49: Chapter 1 33+R,S DRUG ANCHOR R MOLE
Page 50 and 51: Chapter 1 35solubilized in hot etha
Page 52 and 53: Chapter 2 37RsORmRmRsRLRL RRRLH - A
Page 54 and 55: Chapter 2 39The stereochemistry and
Page 56 and 57: Chapter 2 41An asymmetric reducing
Page 58 and 59: Chapter 2 43This approach clearly e
Page 60 and 61: Chapter 2 45PhaxeqP 1MP 2axeqPhP 2M
Page 62 and 63: Chapter 2 47pyrrolidine ] 20 , LAH-
Page 64 and 65: Chapter 2 49Enzymatic reactions are
Page 66 and 67: Chapter 2 51As [ES] in equation 4 c
Page 68 and 69: Chapter 2 53E+AK 1AK -1AEAK 2AE+PE+
Page 70 and 71: Chapter 2 552.2.4 Lipases.Most lipa
Page 72 and 73: Chapter 2 57enzyme intermediate can
Page 74 and 75: Chapter 2 59projecting above the pl
Page 76 and 77: Chapter 2 612.3.1.1. Step 1: Adduct
Page 78 and 79: Chapter 2 63A -+ ROHRO - + AH'RO 2
Page 80 and 81: Chapter 2 65There are various effec
Page 82 and 83:
Chapter 2 67The reactions were foun
Page 84 and 85:
Chapter 2 69Yamanaka and coworkers
Page 86 and 87:
Chapter 2 71sodium or potassium car
Page 88 and 89:
Chapter 3 73The reaction is quite s
Page 90 and 91:
Chapter 3 75literature as the best
Page 92 and 93:
Chapter 3 77dry solvents and, is ch
Page 94 and 95:
Chapter 3 79XXOH+ H 2 NDry K 2 CO 3
Page 96 and 97:
Chapter 3 81substituents are the mo
Page 98 and 99:
Chapter 3 83induces a rotation of t
Page 100 and 101:
Chapter 3 85very sharp and it was p
Page 102 and 103:
Chapter 3 87Raney NickelOH Br MeOH;
Page 104 and 105:
Chapter 4 8933a-m were hydrolysed t
Page 106 and 107:
Chapter 4 91benzo[b]furane (entries
Page 108 and 109:
Chapter 4 93hydroxy or amine groups
Page 110 and 111:
Chapter 4 95the products with ethyl
Page 112 and 113:
Chapter 4 97NCO 2 HNCO 2 H(±)34c(-
Page 114 and 115:
Chapter 4 99NNH37CO2EtOH(±)-27a(+)
Page 116 and 117:
Chapter 4 101As already outlined ab
Page 118 and 119:
Chapter 4 103(+)-(S)-2-octylimidazo
Page 120 and 121:
Chapter 4 105CNNH N2 NCN nC 6 H 13N
Page 122 and 123:
Chapter 4 107key step is the conver
Page 124 and 125:
Chapter 4 109reverse addition in th
Page 126 and 127:
Chapter 4 111which was eliminated e
Page 128 and 129:
Chapter 4 113separate (±)-57a and
Page 130 and 131:
Chapter 5 115to avoid this side rea
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Chapter 5 117Complete degradation o
Page 134 and 135:
Chapter 5 119Entry R T °C Product
Page 136 and 137:
Chapter 5 1212:1:3 in weight. All t
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Chapter 5 123reaction conditions we
Page 140 and 141:
Chapter 5 125Entry Substrate R Time
Page 142 and 143:
Chapter 5 127experiments. But it wa
Page 144 and 145:
Chapter 5 129OClOSAM IIPH=7; R.T.OH
Page 146 and 147:
Chapter 5 131OHOXHOHRHK 2 CO 3 ; Me
Page 148 and 149:
Chapter 6 133HCuSO 4 .5H 2 O,NH 4 O
Page 150 and 151:
Chapter 6 1356.2.1 Heteroannullatio
Page 152 and 153:
Chapter 6 137This discovery allowed
Page 154 and 155:
Chapter 6 139OH(±)-62OHFigure 6.1
Page 156 and 157:
Chapter 6 141Entry Substrate R Time
Page 158 and 159:
Chapter 6 143HOH58-a-c,e,h-lRPdCl 2
Page 160 and 161:
Chapter 6 145afforded the benzo[b]f
Page 162 and 163:
Chapter 6 147RR[P(Ph) 3 ]Pd°OHOPh
Page 164 and 165:
Chapter 6 149H2-IodophenolOHOH(±)-
Page 166 and 167:
Chapter 6 151presence of base as de
Page 168 and 169:
Chapter 7 153A chiral lithium alumi
Page 170 and 171:
Chapter 7 155derivatives were tried
Page 172 and 173:
Chapter 7 157Finally an hypothesis
Page 174 and 175:
Chapter 8 159were washed with a sat
Page 176 and 177:
Chapter 8 16145 min, the mixture wa
Page 178 and 179:
Chapter 8 1638.9 Decarboxylation of
Page 180 and 181:
Chapter 8 165Alcohol 27a (0.2 mmol)
Page 182 and 183:
Chapter 8 167for 48 h. After coolin
Page 184 and 185:
Chapter 8 169room temperature for t
Page 186 and 187:
Chapter 8 171in CH 2 Cl 2 and washe
Page 188 and 189:
Chapter 8 1738.26 Screening of lipa
Page 190 and 191:
Chapter 8 175Na 2 SO 4 . After remo
Page 192 and 193:
Chapter 8 177NMR and MS analysis we
Page 194 and 195:
Chapter 8 179Argon was bubbled thru
Page 196 and 197:
Chapter 8 181IR (CHCl 3 ): ν cm-1=
Page 198 and 199:
Chapter 8 183GC-MS: 305 M + (68%),
Page 200 and 201:
Chapter 8 185[α] 20 D -5.7 (c 1.75
Page 202 and 203:
Chapter 8 187Synthetic method 7.7.1
Page 204 and 205:
Chapter 8 189(R,S)-(±)-1-(2-Octyl)
Page 206 and 207:
Chapter 8 191M.P. = oil.Elementary
Page 208 and 209:
Chapter 8 193Synthetic method 7.11.
Page 210 and 211:
Chapter 8 195(±)-N-1-(2-Octyl)-2-t
Page 212 and 213:
Chapter 8 197IR (CHCl 3 ) ν cm-1 =
Page 214 and 215:
Chapter 8 199(±)-1-(4-Fluorophenyl
Page 216 and 217:
Chapter 8 201Physical and spectral
Page 218 and 219:
Chapter 8 203(±)-1-(Phenyl)-2-prop
Page 220 and 221:
Chapter 8 205128.61, 128.87, 130.39
Page 222 and 223:
Chapter 8 207min.Physical and spect
Page 224 and 225:
Chapter 8 20913C J MOD NMR (CDCl 3
Page 226 and 227:
Chapter 8 211(±)-2'-Methylphenyl-2
Page 228 and 229:
Chapter 9 213References chapter 1:1
Page 230 and 231:
Chapter 9 21531) De Felice, R.; Joh
Page 232 and 233:
Chapter 9 21768) Brodie, A.M.H. in
Page 234 and 235:
Chapter 9 219112) Brodie, A. M. H.;
Page 236 and 237:
Chapter 9 2214) Karabatsos, M.C. J.
Page 238 and 239:
Chapter 9 22334c) Blow D. Nature 19
Page 240 and 241:
Chapter 9 22567a) Kundu, N.G.; Pal,
Page 242:
Chapter 9 22712) Thompson,A.S.; Hum
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