(1S,2R,4R,5R)-tert-Butyl N-(4-hydroxy­methyl-6-oxabi­cyclo­[3.1.0]­hex-2-yl)­carbamate

The title compound, C₁₁H₁₉NO₄, is a precursor for the preparation of (1S,2R,4R)-4-amino-2-(hydroxy­methyl)­cyclo­pentanol, which is an important carbocyclic analogue of β-2-deoxy­ribosyl­amine. The crystal packing of the title compound is stabilized by intermolecular O—H...O hydrogen bonds.

[N,N'-Diphenyl­ureato(2-)][phthalo­cyaninato(2-)]titanium(IV)

In the title complex, [Ti(C₃₂H₁₆N₈)(C₁₃H₁₀N₂O)], the geometry around the Ti atom is square pyramidal, with the four isoindoline N atoms forming the basal plane and the ureate group at the apical site. The crystal structure is formed by close packing of centrosymmetric dimers, consisting of slightly offset mol­ecules related by a crystallographic center of inversion in a face-to-face manner.

(1R,3R)-Methyl 6-tert-butoxy­carbonyl­amino-1,5-dioxo-2,3-di­hydro-5H-1,3-thia­zolo­[3,2-a]­pyridine-3-carboxyl­ate

The absolute configuration has been determined for the title compound, C₁₄H₁₈N₂O₆S, a fluorescent dipeptide analogue, which can act as a rigid backbone chromophore in peptides. Intermolecular N—H...O=C hydrogen bonds [H...O = 2.37 (2) Å] are observed in the crystal packing.

1,1-Di­methyl­hydrazinium chloride

The reaction of 1,1-di­methyl­hydrazine with a solution of HCl in Et₂O affords the anhydrous salt Me₂N(H)NH₂⁺·Cl^-. The crystal structure, determined by X-ray analysis, consists of two independent [Me₂N(H)NH₂]⁺ cations and two Cl^- anions, which are connected via hydrogen bonds.

(3R,6S,7R,8R,9S,9aS)-Meth­yl 6,9-diacet­oxy-7,8-diazido­perhydro-5-oxothia­zolo[3,2-a]azepine-3-carboxyl­ate

The absolute configuration has been determined for the bicyclic title compound, C₁₄H₁₇N₇O₇S, an inter­mediate in the synthesis of fixed chiral bis­(1,2-amino­hydr­oxy) compounds. In the crystal structure, the chair conformation of the seven-membered lactam ring exhibits four axial heteroatom substituents. The fused five-membered thia­zolidine ring prevents inversion of the seven-membered iduronic acid ring derivative to the thermodynamically more favourable chair conformation with four equatorial substitutions.

(3R)-Meth­yl 6-tert-butoxy­carbonyl­amino-5-oxo-2,3-dihydro-5H-1,3-thia­zolo[3,2-a]pyridine-3-carboxyl­ate

The absolute configuration has been determined for the title compound, C₁₄H₁₈N₂O₅S, a bicyclic aromatic building block which can act as a rigid fluorescence marker in peptide backbones. In the crystal packing, the two independent molecules of the asymmetric unit are aligned in an antiparallel manner as dimers which are stabilized by antiparallel inter­molecular N—H...O=C hydrogen bonds. In addition, there are weak inter­molecular C—H...O inter­actions.

(3aS,4S,4aS,7R,9S,9aS)-Methyl 4-benzyloxy-9-methyl­sulfonyloxy-2,2-dimethyl-8-oxoocta­hydro-1,3-dioxa-5-thia-7a-azacyclopenta[f]azulene-7-carboxyl­ate toluene solvate

The absolute configuration has been determined for the title compound, C₂₁H₂₇NO₉S₂·C₇H₈. The compound is a precurser in the synthesis of bicyclic dipeptide isosteres based on mannuronic acid. The seven-membered lactam ring adopts a rigid chair conformation.