NATURE OF VITAMIN B12S
NATURE OF VITAMIN B12S
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DOI：
10.1021/ja01065a057
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发表时间：
1964-01-01
影响因子：
15
通讯作者：
ABBOTT, JC
中科院分区：
文献类型：
--
作者：
COLLAT, JW;ABBOTT, JC
除了全合成方法外，还通过（a）钯碳催化脱氢环A2· 3或B3芳香族前体，（B）酸消除环A芳香族化合物中的烯丙基羟基并随后重排双键，4和（c）热解AMi 6-三烯然后二氧化硒脱氢制备1环AB芳香族甾体。6我们现在希望报道通过一种新的离子方法6从非芳族中间体部分合成环AB芳族甾体，并消除C-19甲基。此外，该方法提供了制备具有多种C-17取代基如二羟基丙酮部分的环AB芳族甾族化合物的方法。当21-乙酰氧基-9 α，11/3-二氯-17-羟基孕甾-1，4-二烯-3，20-二酮（Ia）7在二甲基甲酰胺中回流0.5小时时，或在吡啶中至少6小时，得到两种主要产物，每种产率为20-25%。一种产物被指定为结构21-乙酰氧基-17-羟基孕甾-1，4，8（14），9（11）-四烯-3，20-二酮（II），8 mp 249-252; XieH 241 µ（c 18，900）; nmr（SiMei）：5.72 ppm（C-II乙烯基）;马来酸酐加合物，mp 230-237。另一种产物的结构命名为21-乙酰氧基-3，17 α-二羟基-19-去甲孕甾-1，3，5（10），6，8-五烯-20-酮（伊利亚），X“H分别为230、270、280、292、327和341 µ（e分别为66，000、4780、5520、3980、2280和2650）。相应的3，17-二乙酸酯IIIb的NMR光谱在0.58ppm（C-18甲基）和2.22和2.39ppm（乙酸酯甲基）处显示甲基的信号。
Apart from total synthetic methods, 1 ring AB aromatic steroids havebeen prepared by (a) palladium-carbon-catalyzed dehydrogenation of a ring A2· 3 or B3 aromatic precursor,(b) acid elimination of an allylic hydroxyl group in a ring A aromatic compound with subsequent rearrangement of double bonds, 4 and (c) pyrolysis of a AMi6-triene followed by selenium dioxide dehydrogenation. 6 We now wish to report the partial synthesis of ring AB aromatic steroids from non-aromatic intermediates by a new ionic method6 with elimination of the C-19 methyl group. This method, moreover, provides a means of preparing ring AB aromatic steroids with a variety of C-17 substituents, such as the dihydroxyacetone moiety. When 21-acetoxy-9a, 11/3-dichloro-17-hydroxy preg-na-l, 4-diene-3, 20-dione (la) 7 was refluxed in dimethyl-formamide for 0.5 hr., or in pyridine for at least 6 hr., two major productsresulted, each in 20-25% yield. One product was assigned the structure 21-acetoxy-17-hydroxy pregna-1, 4, 8 (14), 9 (11)-tetraene-3, 20-dione (II), 8 mp 249-252; XieH 241 µ (c 18,900); nmr (SiMei): 5.72 ppm (C-ll vinyl); maleic anhydride adduct, mp 230-237. The other product was as-signed the structure 21-acetoxy-3, 17a-dihydroxy-19-norpregna-l, 3, 5 (10), 6, 8-pentaen-20-one (Ilia), X “'H 230, 270, 280, 292, 327, and 341 µ (e 66,000, 4780, 5520, 3980, 2280, and 2650, respectively). The nmr spectrum of the corresponding 3, 17-diacetate Illb showed signals for methyl groups at 0.58 ppm (C-18 methyl) and at 2.22 and 2.39 ppm (acetate methyl).