3- -5,6-dihydro-7/7-pyrrolo

Azomethine ylides of pyrrolo[l,2- ]pyrazine <1996JOC4655> and 3,4-dihydro pyrrolo[l,2-tf]pyrazine <1997T9341> undergo 1,3-dipolar cycloadditions with a number of dipolarophiles. For example, the ylide 178 reacts with propargylic ester 179 to give the tricyclic derivative 180 (Equation 43). 

A photochemical preparation of a Cephalotaxus alkaloid synthon (20) has been reported (Scheme 2).10 The readily accessible maleimide (17) was iodinated with iodine and silver trifluoroacetate, in 71% yield, and the resulting compound was transformed in two steps (70% overall yield) into the methylene-pyrrolone (18) by the action of methylmagnesium iodide followed by dehydration. Irradiation of (18) afforded (19) (46% yield), which, by successive hydrogenation and reduction with lithium aluminium hydride, gave the dihydro-pyrrolo[2,l-b][3]benzazepine (20). This derivative has served as a key intermediate in the total synthesis of cephalo-taxine described previously (see Vol. 7 of these Reports). 

The use of bifunctional lactim ethers in the above reaction forms the new heterocyclic system pyrimido[4,5-6]tetrahydroazepine,36 37 and is a new method for the synthesis of alloxazines,42 7H-5,6-dihydro-pyrrolo[2,3-d]pyrimidines,38 39 and 8H-piperido[2,3-d]pyrimidines25, 115 (Scheme 21). 

The most general synthesis of substituted 6,7-dihydro-5/f-pyrrolo[l,2-a]imidazoles has been described in several patents. The starting materials are pyrrolidine derivatives such as the 2-iminopyrrolidine or 2-pyrrolidone (Scheme 8) <89EUP306300, 92MI 802-01 >. In the first case, the 2-iminopyrrolidine reacts with the chloroketone (57) at 40°C to give the dihydro pyrrolo[l,2-a]im-idazole (58). In the second case the 2-pyrrolidone was A -acylated by 4-picolyl chloride and the product (59) cyclocondensed with a nitrile to give the 2,3-diaryl-6,7-dihydro-5//-pyrrolo[l,2-a]im-idazole (60). 

Methyl-1,3-dihydropyrrolo[ 1,2-c]thiazole-6,7-biscarbamates have been described as active compounds against murine P388 lymphocytic leukemia <87JMC2109>. Several 5-aryl-2,3-dihydro-pyrrolo[2,l-fe]thiazole-6,7-dimethanol-6,7-bis(isopropylcarbamate)s were tested for growth inhibitory activity with the HL-60 human promyelocytic leukemia cell line. The 5-phenyl, 5-(4-fluorophenyl), and 5-(3,4-dichlorophenyl) have antileukemic activity. These compounds were also cytotoxic to HT-29 human colon carcinoma cells <88JMC1427>. 

Bis (4-chlorophenyl)-2,5-dihydro-pyrrolo [3,4-c] pyrrole-1,4-dione. See Pigment red 254... 

Bibydro- [benzo-1, 2 t 3.4-naphtho-2".l 6.7-(1.2.5.heptatriazia)] 26 H 52. 4 -Phenyl-4. 5 -dihydro- [pyrrolo-2. 3 2.3-chinozalin] 26II52. [Athyl-metheiwl]-[2-(2-amino-plieny])-booziinidazd] 26,... 

Compound fert-butyl 3-(2-methoxy-2-oxoethyl)-lH-indole-l-carboxylate (m-23a) [89], terf-butyl 3-formyl-5-methoxy-lff-indole-l-carboxylate [241], (3R,7aS)-3-(trichloromethyl)-tetrahydropyrrolo[l,2-c]oxazol-l(3F/)-one (III-43) [118], (3R, 7aR)-7a-allyl-3-(trichloromethyl)-tetrahydropyrrolo[ 1,2-c]oxazol-1 (3H)-one (HI-45) [121], (3R,7a5)-3-(tert-butyl)dihydro-pyrrolo[l,2-c]oxazole-l,5(3//,6//)-dione (III-46a) [125], (3R,7a5)-3-(trichloromethyl)-dihydropyrrolo[ 1,2-c]oxazole-... 

Kogan N.A., Vlasova M.I. Cyclisation of 2-indoilhydrazones in dihydro-pyrrolo[4,5-b]indole derivatives and their isomerisation in pyridazino[4,5-b]indoles . Chem. ofHet. Comp. 1972, Rq 2, p. 279-280. (Russian)... 

Systemahe name l- Mcthylthio)-2-methyl-5,6-dihydro-4f/-pyrrolo[3,2,l-ijjquinoline. 

Pyrrolo[2,3-6]pyridine, 2,3-dihydro-electrophilic substitution, 4, 503 nitration, 4, 512 synthesis, 4, 520... 

Pyrrolo[3,2-6]pyridine, 2-methyl-synthesis, 4, 527 Pyrrolo[3,2-c]pyridine, 4-amino-nucleophilic reactions, 4, 507 Pyrrolo[3,2-c]pyridine, 2,3-dihydro-reactions, 4, 512... 

Pyrrolo[3,4-6]quinoxaline, 2-/-butyl-1,3-dihydro-oxidation, 4, 509 Pyrrolo[3,2-d Jselenazoles synthesis, 6, 344, 1009... 

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