9 perhydropyrido oxazin-1-ones, reduction

Reduction of a perhydropyrido[l,2-c][l,4]oxazin-l-one with BH3 in anhydrous THF at room temperature yielded a perhydropyrido[l,2-c] [l,4]oxazine (OOMIPl). 

Reduction of perhydropyrido[l,2-c][l,3]oxazin-l-ones with Zn in AcOH yielded ring-opened products (06OBC1587). 

Catalytic reduction of compound 467 over Pd(OH)2/C catalyst in MeOH for 1 h, then reaction with L-lysine derivative 468 for 24 h gave an inseparable mixture of perhydropyrido[2,l-c][l,4]oxazin-3-one 215 and piperidine 469 (08BMC10216). 

JOC6700). The 1-methyl derivative of 231 (R1 = Me) was accompanied by 10% of the C-l epimer. Reduction of oxazolo[3,2-a]pyrimidine-5-carboxylates 232 with Zn(BH4)2 gave an epimeric mixture of 4-phenylper-hydropyrido[2,l-c][l,4]oxazin-l-one (233) (94JOC3769). When 232 reacted with BF3-etherate at -10°C in THF, then with Grignaird reagents at -78°C, epimeric mixtures of 4-phenyl-6-substituted perhydropyrido-[2,1 -c] [ 1,4]oxazin-1 -ones (234) were isolated after treatment with 2N HC1. 

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