Masaru Okutsu

A new synthesis of inosine from 5-amino-1-beta-D-ribofuranosyl-4-imidazole-carboxamide.

Inosine was prepared (15% yield) by treatment of 5-amino-1-beta-D-ribofuranosyl-4-imidazolecarboxamide (AICA-riboside) with chloroform in the presence of sodium methoxide. This ring closure can be reasonably explained by assuming the formation of dichlorocarbene from chloroform and alkali. Carbon tetrachloride or hexachloroethane as a carbene source was more effective for the ring closure of AICA-riboside, giving inosine in 48% and 51% yields respectively.

Further study on effects of N-β-phenylpropionyl-l-tyrosine and its derivatives on the excitability of an identifiable giant neuron of Achatina fulica Féerussac

Abstract 1. The marked inhibitory effects of N-β- phenylpropionyl- l -tyrosine (the critical concentration, C.C., 3 × 10 −7 -10 −7 m) and N-β- phenylpropionyl- l -tryptophan (C.C., 10 −7 M) on a giant neuron (TAN. tonically autoactive neuron) of Achatina fulica Ferussac, have been previously demonstrated. The effects of their newly synthesized derivatives were compared. 2. N-β-(3- Chlorophenyl)propionyl- l -tyrosine and N-β-(3- chlorophenyl)propionyl- l -tryptophan . having a chlorine in the phenyl group, showed inhibitory effects (C.C., 3 × 10 −5 M) weaker than those of the two original compounds. 3. Effects of N- phenylpropargyloyl- l -tyrosine (C.C., 3 × 10 −6 M) and N- phenylpropargyloyl- l -tryptophan (C.C.,10 −6 M), having a triple bond in the carbon chain attached to the phenyl group, were similar to or slightly weaker than those of the original compounds. 4. Effects of N- cinnamoyl- l -tyrosine and N- cinnamoyl- l -tryptophan (C.C., 3 × 10 −5 M), having a double bond in the same carbon chain, were less inhibitory. 5. Effects of N-β- phenylpropionyl- l -p- methoxyphenylalanine and N-β- phenylpropionyl- l -5- hydroxytryptophan (C.C., 3 × 10 −5 M) were also much weaker.

Further study on effects of and its derivatives on the excitability of an identifiable giant neuron of Achatina fulica Féerussac

Abstract 1. The marked inhibitory effects of N-β- phenylpropionyl- l -tyrosine (the critical concentration, C.C., 3 × 10 −7 -10 −7 m) and N-β- phenylpropionyl- l -tryptophan (C.C., 10 −7 M) on a giant neuron (TAN. tonically autoactive neuron) of Achatina fulica Ferussac, have been previously demonstrated. The effects of their newly synthesized derivatives were compared. 2. N-β-(3- Chlorophenyl)propionyl- l -tyrosine and N-β-(3- chlorophenyl)propionyl- l -tryptophan . having a chlorine in the phenyl group, showed inhibitory effects (C.C., 3 × 10 −5 M) weaker than those of the two original compounds. 3. Effects of N- phenylpropargyloyl- l -tyrosine (C.C., 3 × 10 −6 M) and N- phenylpropargyloyl- l -tryptophan (C.C.,10 −6 M), having a triple bond in the carbon chain attached to the phenyl group, were similar to or slightly weaker than those of the original compounds. 4. Effects of N- cinnamoyl- l -tyrosine and N- cinnamoyl- l -tryptophan (C.C., 3 × 10 −5 M), having a double bond in the same carbon chain, were less inhibitory. 5. Effects of N-β- phenylpropionyl- l -p- methoxyphenylalanine and N-β- phenylpropionyl- l -5- hydroxytryptophan (C.C., 3 × 10 −5 M) were also much weaker.

Further study on effects of N-β-phenylpropionyl--tyrosine and its derivatives on the excitability of an identifiable giant neuron of Achatina fulica Féerussac

Abstract 1. The marked inhibitory effects of N-β- phenylpropionyl- l -tyrosine (the critical concentration, C.C., 3 × 10 −7 -10 −7 m) and N-β- phenylpropionyl- l -tryptophan (C.C., 10 −7 M) on a giant neuron (TAN. tonically autoactive neuron) of Achatina fulica Ferussac, have been previously demonstrated. The effects of their newly synthesized derivatives were compared. 2. N-β-(3- Chlorophenyl)propionyl- l -tyrosine and N-β-(3- chlorophenyl)propionyl- l -tryptophan . having a chlorine in the phenyl group, showed inhibitory effects (C.C., 3 × 10 −5 M) weaker than those of the two original compounds. 3. Effects of N- phenylpropargyloyl- l -tyrosine (C.C., 3 × 10 −6 M) and N- phenylpropargyloyl- l -tryptophan (C.C.,10 −6 M), having a triple bond in the carbon chain attached to the phenyl group, were similar to or slightly weaker than those of the original compounds. 4. Effects of N- cinnamoyl- l -tyrosine and N- cinnamoyl- l -tryptophan (C.C., 3 × 10 −5 M), having a double bond in the same carbon chain, were less inhibitory. 5. Effects of N-β- phenylpropionyl- l -p- methoxyphenylalanine and N-β- phenylpropionyl- l -5- hydroxytryptophan (C.C., 3 × 10 −5 M) were also much weaker.