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8a-pyrrolizidine

Pyrrolizidine ethers can be obtained by alkylation. Culvenor and Smith104 used this reaction in partial synthesis of the recently discovered alkaloids l-methoxymethyl-l,2-dehydro-8a-pyrrolizidine (158a) and 7hydroxy-1 -methoxymethyl-1,2-dehydro-8 a-pyrrolizi-dine (158b). The compounds were obtained by alkylating supinidine (157a) or retronecine (157b) with methyl iodide in the presence of... [Pg.356]

The hydroxy groups of pyrrolizidine amino-alcohols are readily replaced by chlorine atoms upon treatment with thionyl chloride (see, e.g., refs. 101 and 103). In this reaction, the allylic hydroxyl group is more reactive and can be selectively replaced by chlorine.79 In some particular cases, methoxyl groups can also be substituted for halogen e.g., l/3-methoxymethyl-8a-pyrrolizidine, when treated with hydro-bromic acid, gives rise to the corresponding bromo derivative.104... [Pg.356]

Heliotrine (161) Small Gram-ve coccus 7 a-Hydroxy-1 -methylene-8a-pyrrolizidine (173) (-) 165... [Pg.377]

Europine (165) Peptococcus heliotrinreducans (7a-Hydroxy-l-methylene-8a-pyrrolizidine) (173) (-) 166... [Pg.377]

Isoretronal (lB-hydroxymethyl-8a-pyrrolizidine) Sup1n1dine (1-hydroxymethyl-1,2-dehydro-8a- 115-16/1.5 39-40 7.4... [Pg.30]

Hydrogenation of (11) gave the IjS-hydroxymethyl isomer (12), since it afforded dihydroxyheliotridane (2) on hydrolysis. Jones oxidation of (12) gave the corresponding carboxylic acid, the ethyl ester of which epimerised at C-1 and also suffered transesterification when treated with sodium methoxide, to give la-methoxycarbonyl-7a-hydroxy-8a-pyrrolizidine (13). Reduction of (13)... [Pg.60]

Methoxymethyl-1,2-epoxypyrrolizidine, 1 -methoxymethyl-A13- dehydro-8a-pyrrolizidine, 1 -methoxymethyl-A 2 dehydro-7P-hydroxy-8a-pyrrolizidine, ip,2P-epoxy-la-hydroxymethyl-8a-pyrrolizidine,... [Pg.118]

Platynecine 7 jS-Hydroxy -1 jS-hydroxymethyl-(8a) -pyrrolizidine Mikanoidine Plat5 hylline Sarracine 151-152 -57.0° ... [Pg.57]

Optically active fixed the double bond at the 1,2-position (138). Moreover, supinidine was thereby shown to be in the same stereochemical series as isoretronecanol (CXV) and (—)-heliotridane (CXXVIII) with the absolute configuration at Cg in isoretronecanol fixed as a (166), the complete representation of supinidine becomes CXXXI, 1-hydroxy-methyl-A -dehydro-(8a)-pyrrolizidine. The hydrogenations of supinine... [Pg.60]

Moreover, these workers were able to establish the relative configurations at the four asymmetric centers in the necine. Absolute configurations may now be assigned (166), so that rosmarinecine is fully described as 2a,7/3-dihydroxy-l -hydroxymethyl-(8a)-pyrrolizidine (CLV). [Pg.66]

Hydroxy-1 -methylene-8a-pyrrolizidine Occurs free as the base 35-36 -150 d... [Pg.263]

Heliotridine 7 a-Hydroxy-1 -hydroxymethyl-l,2-dehydro-8a-pyrrolizidine 7 - Angelylheliotridine Angelyl heliotridine trachelanthate Angelyl heliotridine viridiflorate ... [Pg.263]

Crotanecine 6, 7 jS-Dihydroxy-1 -hydroxymethyl-1,2-dehydro-8a-pyrrolizidine Anaerotine ... [Pg.263]

See other pages where 8a-pyrrolizidine is mentioned: [Pg.356]    [Pg.377]    [Pg.377]    [Pg.30]    [Pg.30]    [Pg.30]    [Pg.30]    [Pg.30]    [Pg.30]    [Pg.59]    [Pg.117]    [Pg.118]    [Pg.118]    [Pg.55]    [Pg.56]    [Pg.56]    [Pg.57]    [Pg.61]    [Pg.66]    [Pg.263]    [Pg.264]    [Pg.264]    [Pg.264]    [Pg.264]    [Pg.264]    [Pg.264]    [Pg.265]    [Pg.265]    [Pg.266]    [Pg.266]    [Pg.266]    [Pg.267]    [Pg.268]   
See also in sourсe #XX -- [ Pg.549 ]



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