Quinolines. IV. Some Bz-Iodo-3-methyl-4-(1'-methyl-4'-diethylaminobutylamino) -quinolines

Multiple Regioselective Functionalizations of Quinolines via Magnesiations

“…Similarly, starting from 2,4-dibromoquinoline ( 9b ), the addition of 4 (1.1 equiv, −78 °C, 2 h) gave the corresponding 4-magnesiated 2-bromoquinoline ( 10b ). In contrast, the reactions of 2,3,4-tribromoquinoline ( 9c ) or 3,4-dibromoquinoline ( 9d ) with i PrMgCl·LiCl ( 4 ) were not selective and provided regioisomeric mixture of Grignard reagents. Related selectivity problems have been observed with dibromopyridines. , However, using the sterically more demanding MesMgBr·LiCl ( 5 , 1.1 equiv, −10 °C, 3 h), a complete regioselective magnesiation at the C3 position was observed for the 2,3,4-tribromoquinoline ( 9c ), providing the corresponding intermediate 10c (Table ).…”

Organic chemistry

“…Autoxidation of cholesterol (and other A5-steroids) in aqueous colloidal solution gives the epimeric 3( p) : 7-dihydroxycholestenes (and analogous compounds) ; the 7" p "-compound had previously been prepared,g1 and it now appears that the 7" a "-compound, resulting from 7-ketocholesterol by reduction with aluminium i s o p r o p ~x i d e , ~~ is a mixture of epimerides containing up to 20% of the 7ccp"-compound;93 the same may be expected t o be true of one of the epimeric 3(a) : 7-dihydro~ycholestenes.~ Although one of the epimeric 3(p) : 7-dibenzoyloxycholestenes should be subject to steric hindrance at C,, both by treatment with cold sodium methoxida give 7-monobenzoates.93* 95 Differences in reactivity are disclosed in elimination reactions, wherein the 7"a "-compounds readily give cholest-7-ene derivatives, whilst the 7" p "-compounds are resistant. [93][94][95][96] There is thus no direct evidence upon which an assignment of configuration at C, in the sterol series can be based; 97 a correlation with the known orientation of the 7-hydroxyl group in the bile acids (XLVII), (L), and (LII) is much to be desired. Indirect evidence based on optical rotatory powers permits, however, a provisional allocation.…”