1.3.4.5.6.7.116- Hexahydro-2//-pyrimido structure

Characteristic H NMR data of (4a/ ,55)- and (4n5,5R)-2-substituted 5- [A-(/e/ /-butoxycarbonyl)-L-tryptophyl]amino perhydropyrido[l,2-c]pyri-midine-l,3-diones were tabulated (01JMC2219). C CPMASS NMR data of 4-(4-methoxyphenyl)perhydropyrido[l,2-c]pyrimidine were reported (00JST73). C NMR data were reported for eight 4-aryl-2,3,5,6,7,8-hexahydro-l//-pyrido[l,2-c]pyrimidin-l,3-diones in the solid state and in CDCI3 solution (00JPO213). The structure of 4-aryl-3,4-dihydro-2//-pyrido [l,2-c]pyrimidine-l,3-diones and their 2,3,5,6,7,8-hexahydro derivatives were characterized by H and C NMR data (99JHC389). Conformational analysis of 6-methyl-2,3,4,6,7,ll/)-hexahydro-l//-pyrimido[6,l-n]isoquino-lin-2-ones 138 and 139 were carried out by H and C NMR studies (97LA1165). 

Various heterocyclic structures, among them 3-substituted-hexahydro-277-pyrimido[l,2- ]pyrimidin-2-ones 190, have been prepared by solid-phase synthesis. The acetates 187 were reacted with diaminoalkanes, the resulting diamines 188 cyclized with BrCN to the monocyclic compounds 189, which were cleaved and cyclized with Et3N to give 190 (Scheme 30) <2005TL5289>. 

An X-ray crystal structure determination of the [f-Bu3Zn] anion present in 21 has an almost perfect trigonal planar arrangement [Zn—C bond distances 2.080(7), 2.059(7) and 2.057(8) A C-Zn-C angles 118.1(2), 120.7(3) and 120.6(3)°]. Compound 21 was prepared by reacting l,3,4,6,7,8-hexahydro-2//-pyrimido[l,2]pyrimidine, Me2Zn and f-BuLi (equation 9). It is notable that the methyl groups initially bound to zinc all become... 

A dinuclear complex of Pd(III), [Pd2(hpp)4Cl2] (hpp = the anion of 1,3,4,6,7,8-hexahydro-2H-pyrimido[ 1,2-alpyrimidine), has been reported. The four bridging hpp ligands describe a paddle wheel-type structure. This compound presents the shortest Pd-Pd distance ever reported (239.1 pm), shorter than all reported Pd(I)-Pd(I) bonds, and 36 pm shorter than the Pd-Pd distance in the metal itself (42, N N = hpp). 4... 

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