methyl (20R,23S,24R)-4α,24-dimethyl-5α-cholestane-23-carboxylate

• 分子结构分类: 有机化合物 - 脂质和类脂质分子 - 类固醇和类固醇衍生物
• 英文名称: methyl (20R,23S,24R)-4α,24-dimethyl-5α-cholestane-23-carboxylate
• 英文别名: methyl (2S,3R)-3,4-dimethyl-2-[(2R)-2-[(4R,5S,8S,9S,10S,13R,14S,17R)-4,10,13-trimethyl-2,3,4,5,6,7,8,9,11,12,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-17-yl]propyl]pentanoate
• 化学式: C₃₁H₅₄O₂
• 分子量: 458.769
• InChiKey: YNIQJCUVUZMMPH-YJKSBRIFSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  10.7
• 重原子数：
  33
• 可旋转键数：
  7
• 环数：
  4.0
• sp3杂化的碳原子比例：
  0.97
• 拓扑面积：
  26.3
• 氢给体数：
  0
• 氢受体数：
  2

反应信息

• 作为产物：
  描述：

  孕烯醇酮 在 吡啶 、 N-甲基-4-哌啶酮 、 盐酸 、 sodium hydroxide 、 lithium aluminium tetrahydride 、 硼烷四氢呋喃络合物 、 偶氮二异丁腈 、 氨 、 双氧水 、 三正丁基氢锡 、 aluminum isopropoxide 、 lithium 、 对甲苯磺酸 、 溶剂黄146 、 三乙胺 、 sodium iodide 、 lithium diisopropyl amide 作用下， 以 四氢呋喃 、 乙醇 、 二氯甲烷 、 水 、 丙酮 、 甲苯 、 苯 为溶剂， 反应 111.0h， 生成 methyl (20R,23S,24R)-4α,24-dimethyl-5α-cholestane-23-carboxylate
  参考文献：
  名称：

  Synthesis of biological markers in fossil fuels. 7. Selected diastereomers of 4.alpha.-methyl-5.alpha.-stigmastane and 5.alpha.-dinosterane

  摘要：

  Efficient routes for the preparation of selected C-23 and C-24 diastereomers of the C30 biological markers 4alpha-methyl-5alpha-stigmastane (1) and 5alpha-dinosterane (2) involved the alkylation of 20-(iodomethyl)-4alpha-methyl-5alpha-pregnane with either saturated or alpha,beta-unsaturated esters. The alkylation of (20S)-20-(iodomethyl)-4alpha-methyl-5alpha-pregnane with methyl (3R)-3-ethyl-4-methylpentanoate furnished methyl (20R,23zeta,24S)-4alpha-methyl-5alpha-stigmastane-23-carboxylate, and a subsequent decarbomethoxylation provided (20R,24R)-l. The alkylation of (20S)-20-(iodomethyl)-4alpha-methyl-5alpha-pregnane with methyl (3S)-3,4-dimethylpentanoate led to methyl (20R,23zeta,24R)-4alpha,24-dimethyl-5alpha-cholestane-23-carboxylate, and the reduction of this mixture provided principally (20R,23S,24R)-5alpha-dinosteran-29-ol. The further reduction of the mesylate of this isomer secured (20R,23S,24R)-5alpha-dinosterane (2a). The application of the same sequence of reactions using methyl (3R)-3,4-dimethylpentanoate led principally to (20R,23R,24S)-5alpha-dinosterane (2d). The alkylation of (20S)-20-(iodomethyl)-4alpha-methyl-5alpha-pregnane with methyl (2zeta)-3,4-dimethyl-2-pentanoate and a subsequent reduction of the ester provided a separable mixture of (20R,23R)- and (20R,23S)-5alpha-dinoster-24-(28)-en-29-ol in a 2.4:1 ratio. The conversion of (20R,23R)-5alpha-dinoster-24(28)-en-29-ol to the corresponding tert-butyldimethylsilyl ether, reduction of the DELTA24(28) bond with hydrogen over platinum oxide, and deprotection gave principally (20R,23R,24R)-5alpha-dinosteran-29-ol. The further reduction of this alcohol provided (20R,23R,24R)-5alpha-dinosterane (2b). The application of the same sequence of reactions to (20R,23S)-5alpha-dinoster-24(28)-en-29-ol provided (20R,23S,24S)-5alpha-dinosterane (2c). Diastereoselectivity at the C-23 position in these ester alkylations was examined as a function of stereochemistry at both the C-20 and C-24 positions.

  DOI：

  10.1021/jo00064a039

文献信息

• Synthesis of biological markers in fossil fuels. 7. Selected diastereomers of 4.alpha.-methyl-5.alpha.-stigmastane and 5.alpha.-dinosterane
  作者：Ivan Stoilov、Ewa Kolaczkowska、David S. Watt、Jan St. Pyrek、Robert M. K. Carlson、Frederick J. Fago、J. Michael Moldowan

  DOI：10.1021/jo00064a039

  日期：1993.6

  Efficient routes for the preparation of selected C-23 and C-24 diastereomers of the C30 biological markers 4alpha-methyl-5alpha-stigmastane (1) and 5alpha-dinosterane (2) involved the alkylation of 20-(iodomethyl)-4alpha-methyl-5alpha-pregnane with either saturated or alpha,beta-unsaturated esters. The alkylation of (20S)-20-(iodomethyl)-4alpha-methyl-5alpha-pregnane with methyl (3R)-3-ethyl-4-methylpentanoate furnished methyl (20R,23zeta,24S)-4alpha-methyl-5alpha-stigmastane-23-carboxylate, and a subsequent decarbomethoxylation provided (20R,24R)-l. The alkylation of (20S)-20-(iodomethyl)-4alpha-methyl-5alpha-pregnane with methyl (3S)-3,4-dimethylpentanoate led to methyl (20R,23zeta,24R)-4alpha,24-dimethyl-5alpha-cholestane-23-carboxylate, and the reduction of this mixture provided principally (20R,23S,24R)-5alpha-dinosteran-29-ol. The further reduction of the mesylate of this isomer secured (20R,23S,24R)-5alpha-dinosterane (2a). The application of the same sequence of reactions using methyl (3R)-3,4-dimethylpentanoate led principally to (20R,23R,24S)-5alpha-dinosterane (2d). The alkylation of (20S)-20-(iodomethyl)-4alpha-methyl-5alpha-pregnane with methyl (2zeta)-3,4-dimethyl-2-pentanoate and a subsequent reduction of the ester provided a separable mixture of (20R,23R)- and (20R,23S)-5alpha-dinoster-24-(28)-en-29-ol in a 2.4:1 ratio. The conversion of (20R,23R)-5alpha-dinoster-24(28)-en-29-ol to the corresponding tert-butyldimethylsilyl ether, reduction of the DELTA24(28) bond with hydrogen over platinum oxide, and deprotection gave principally (20R,23R,24R)-5alpha-dinosteran-29-ol. The further reduction of this alcohol provided (20R,23R,24R)-5alpha-dinosterane (2b). The application of the same sequence of reactions to (20R,23S)-5alpha-dinoster-24(28)-en-29-ol provided (20R,23S,24S)-5alpha-dinosterane (2c). Diastereoselectivity at the C-23 position in these ester alkylations was examined as a function of stereochemistry at both the C-20 and C-24 positions.