Different hydrogen-bonded chains in the crystal structures of three alkyl N-[(E)-1-(2-benzyl­­idene-1-methyl­hydrazin­yl)-3-hy­dr­oxy-1-oxopropan-2-yl]carbamates

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Abstract

The crystal structures of three methyl­ated hydrazine carbamate derivatives prepared by multi-step syntheses from L-serine are presented, namely benzyl N-{(E)-1-[2-(4-cyanobenzylidene)-1-methylhydrazinyl]-3-hydroxy-1-oxopro­pan-2-yl}carbamate, C₂₀H₂₀N₄O₄, tert-butyl N-{(E)-1-[2-(4-cyanobenzylidene)-1-methylhydrazinyl]-3-hydroxy-1-oxopropan-2-yl}carbamate, C₁₇H₂₂N₄O₄, and tert-butyl N-[(E)-1-(2-benzylidene-1-methylhydrazinyl)-3-hydroxy-1-oxopro­pan-2-yl]carbamate, C₁₆H₂₃N₃O₄. One of them shows that an unexpected racemization has occurred during the mild-condition methyl­ation reaction. In each crystal structure, the mol­ecules are linked into chains by O-HO hydrogen bonds, but with significant differences between them.

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Keywords: Carbohydrazide; methyl­ation; hydrogen bonds; chain; crystal structure Document Type: Research Article DOI: 10.1107/S2056989015010440 Publication date: 6 de Junho de 2015 [:en]

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Abstract

The crystal structures of three methyl­ated hydrazine carbamate derivatives prepared by multi-step syntheses from L-serine are presented, namely benzyl N-{(E)-1-[2-(4-cyanobenzylidene)-1-methylhydrazinyl]-3-hydroxy-1-oxopro­pan-2-yl}carbamate, C₂₀H₂₀N₄O₄, tert-butyl N-{(E)-1-[2-(4-cyanobenzylidene)-1-methylhydrazinyl]-3-hydroxy-1-oxopropan-2-yl}carbamate, C₁₇H₂₂N₄O₄, and tert-butyl N-[(E)-1-(2-benzylidene-1-methylhydrazinyl)-3-hydroxy-1-oxopro­pan-2-yl]carbamate, C₁₆H₂₃N₃O₄. One of them shows that an unexpected racemization has occurred during the mild-condition methyl­ation reaction. In each crystal structure, the mol­ecules are linked into chains by O-HO hydrogen bonds, but with significant differences between them.

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Keywords: Carbohydrazide; methyl­ation; hydrogen bonds; chain; crystal structure Document Type: Research Article DOI: 10.1107/S2056989015010440 Publication date: 6 de Junho de 2015 [:]