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Different hydrogen-bonded chains in the crystal structures of three alkyl N-[(E)-1-(2-benzyl-idene-1-methyl-hydrazin-yl)-3-hy-droxy-1-oxopropan-2-yl]carbamates.

Noguiera TC, Pinheiro AC, Wardell JL, de Souza MV, Abberley JP, Harrison WT - Acta Crystallogr E Crystallogr Commun (2015)

Bottom Line: The crystal structures of three methyl-ated 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-oxopro-pan-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-oxopro-pan-2-yl]carbamate, C16H23N3O4.One of them shows that an unexpected racemization has occurred during the mild-condition methyl-ation reaction.In each crystal structure, the mol-ecules are linked into chains by O-H⋯O hydrogen bonds, but with significant differences between them.

View Article: PubMed Central - HTML - PubMed

Affiliation: Fundação Oswaldo Cruz, Instituto de Tecnologia em Fármacos-FarManguinhos, Rua Sizenando Nabuco, 100, Manguinhos, 21041-250 Rio de Janeiro, RJ, Brazil.

ABSTRACT
The crystal structures of three methyl-ated 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-oxopro-pan-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-oxopro-pan-2-yl]carbamate, C16H23N3O4. One of them shows that an unexpected racemization has occurred during the mild-condition methyl-ation reaction. In each crystal structure, the mol-ecules are linked into chains by O-H⋯O hydrogen bonds, but with significant differences between them.

No MeSH data available.


The mol­ecular structure of (II) showing 50% displacement ellipsoids.
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fig2: The mol­ecular structure of (II) showing 50% displacement ellipsoids.

Mentions: The mol­ecular structure of (II) can be seen in Fig. 2 ▸: again the methyl­ation of N2 has occurred as expected. Because the absolute structure was indeterminate, the configuration of C10 (S) was assumed to be the same as that of the corresponding atom in the l-serine starting material. In terms of the C7/N1/N2/C9/O1 grouping in (II), the C9—N2 and N1—N2 bond lengths are 1.385 (6) and 1.388 (5) Å, respectively, which are both notably longer than the corresponding bonds in (I), and the r.m.s. deviation from planarity of 0.049 Å for these five atoms is also larger than the corresponding value for (I). The dihedral angle between C7/N1/N2/C9/O1 and the C1-benzene ring in (II) is 10.5 (3)°. The C7—N1—N2—C8 torsion angle is 1.2 (7)° and the C9—C10—C11—O2 torsion angle is −47.4 (6)°, which are similar to the equivalent data for (I). The C9—C10—N3—H3 torsion angle in (II) is 30° and the separation between H2A and H3 is 2.7 Å. These values are evidently sufficiently different from the corresponding data for (I) to lead to a different hydrogen-bonding pattern in the crystal (see below).


Different hydrogen-bonded chains in the crystal structures of three alkyl N-[(E)-1-(2-benzyl-idene-1-methyl-hydrazin-yl)-3-hy-droxy-1-oxopropan-2-yl]carbamates.

Noguiera TC, Pinheiro AC, Wardell JL, de Souza MV, Abberley JP, Harrison WT - Acta Crystallogr E Crystallogr Commun (2015)

The mol­ecular structure of (II) showing 50% displacement ellipsoids.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4518986&req=5

fig2: The mol­ecular structure of (II) showing 50% displacement ellipsoids.
Mentions: The mol­ecular structure of (II) can be seen in Fig. 2 ▸: again the methyl­ation of N2 has occurred as expected. Because the absolute structure was indeterminate, the configuration of C10 (S) was assumed to be the same as that of the corresponding atom in the l-serine starting material. In terms of the C7/N1/N2/C9/O1 grouping in (II), the C9—N2 and N1—N2 bond lengths are 1.385 (6) and 1.388 (5) Å, respectively, which are both notably longer than the corresponding bonds in (I), and the r.m.s. deviation from planarity of 0.049 Å for these five atoms is also larger than the corresponding value for (I). The dihedral angle between C7/N1/N2/C9/O1 and the C1-benzene ring in (II) is 10.5 (3)°. The C7—N1—N2—C8 torsion angle is 1.2 (7)° and the C9—C10—C11—O2 torsion angle is −47.4 (6)°, which are similar to the equivalent data for (I). The C9—C10—N3—H3 torsion angle in (II) is 30° and the separation between H2A and H3 is 2.7 Å. These values are evidently sufficiently different from the corresponding data for (I) to lead to a different hydrogen-bonding pattern in the crystal (see below).

Bottom Line: The crystal structures of three methyl-ated 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-oxopro-pan-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-oxopro-pan-2-yl]carbamate, C16H23N3O4.One of them shows that an unexpected racemization has occurred during the mild-condition methyl-ation reaction.In each crystal structure, the mol-ecules are linked into chains by O-H⋯O hydrogen bonds, but with significant differences between them.

View Article: PubMed Central - HTML - PubMed

Affiliation: Fundação Oswaldo Cruz, Instituto de Tecnologia em Fármacos-FarManguinhos, Rua Sizenando Nabuco, 100, Manguinhos, 21041-250 Rio de Janeiro, RJ, Brazil.

ABSTRACT
The crystal structures of three methyl-ated 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-oxopro-pan-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-oxopro-pan-2-yl]carbamate, C16H23N3O4. One of them shows that an unexpected racemization has occurred during the mild-condition methyl-ation reaction. In each crystal structure, the mol-ecules are linked into chains by O-H⋯O hydrogen bonds, but with significant differences between them.

No MeSH data available.