Crystal and molecular structure of 2,6-di (o-chloro)phenyl-3,5-dimethyl-N-nitrosopiperidin-4-one(NOCDMPO)

The title compound (C₁₉H₁₈O₂N₂Cl₂) crystallized in the monoclinic space groupP2₁/n witha=13.062(2),b=10.931(2),c=13.120(2)Å, and=104.57(1)°. The structure was solved by direct methods and refined toR=0.047 for 2776 reflections. The piperidine ring assumes a distorted boat conformation. The angle between phenyl rings is 78.98(7)°. The nitroso group is oriented by 138.22(7)° to the best plane of the piperidine ring. The interaction between the molecules are van der Waals in nature.DCB Contribution No. 814.     

Apparent shortening of the Csp3—Csp3 bond analysed via a variable‐temperature X‐ray diffraction study in racemic 1,1′‐binaphthalene‐2,2′‐diyl diethyl bis(carbonate)

Crystal structure determination at room temperature [292 (2) K] of racemic 1,1′‐binaphthalene‐2,2′‐diyl diethyl bis(carbonate), C₂₆H₂₂O₆, showed that one of the terminal carbon–carbon bond lengths is very short [Csp³—Csp³ = 1.327 (6) Å]. The reason for such a short bond length has been analysed by collecting data sets on the same crystal at 393, 150 and 90 K. The values of the corrected bond lengths clearly suggest that the shortening is mainly due to positional disorder at two sites, with minor perturbations arising as a result of thermal vibrations. The positional disorder has been resolved in the analysis of the 90 K data following the changes in the unit‐cell parameters for the data sets at 150 and 90 K, which appear to be an artifact of a near centre of symmetry relationship between the two independent molecules in the space group P at these temperatures. Indeed, the unit cell at low temperature (150 and 90 K) is a supercell of the room‐temperature unit cell.     

Novel one-step method for the conversion of isothiocyanates to 2-alkyl(aryl)aminothiazoles

2-Aminothiazole derivatives are widely used structural motifs in medicinal chemistry due to their broad application in drug development. Herein we demonstrate a novel one-step method for the synthesis of 2-aminothiazole derivatives from the corresponding isothiocyanates via thiourea formation followed by cycloisomerisation in an intramolecular thia-Michael fashion. This method is very mild, simple and highly efficient and versatile enough to accommodate various amino substitutions at the C2 position of thiazoles. This methodology is equally well applicable to synthesise various 2-substituted amino-5-thiazolylmethylphosphonate derivatives.     

Total synthesis of arenamide A and its diastereomer

Arenamide A and its diastereomer have been synthesized in a convergent fashion. The key steps involved in this synthesis are Sharpless asymmetric epoxidation, C–C bond formation, and macrolactamization.     

A short and common stereoselective approach to 5/6, 6/6, 6/7 bicyclic aza sugars

An efficient and highly stereoselective approach to bicyclic aza sugars is described using Grignard reaction on an N-benzyl imine derived from 3-O-benzyl-1,2-O-isopropylidine-α-d-xylo-pentodialdofuranose, ring closing metathesis, and reductive cyclization as key steps.     

Nucleoside derived amino acids (NDA) in foldamer chemistry: synthesis and conformational studies of homooligomers of modified AZT

Homo short-oligomers of a novel trans-β-amino acid derived from AZT were synthesized and characterized. These adopt right-handed helical turns with their bases positioned systematically along the helix axis. These studies open up new possibilities for synthesizing nucleoside derived functional foldamers.     

Single crystal EPR and optical studies of paramagnetic ions doped zinc potassium phosphate hexahydrate--part II: VO(II)--a case of substitutional site.

Single crystal electron paramagnetic resonance (EPR) studies were carried at room temperature for VO(II) doped zinc potassium phosphate hexahydrate. The results indicate that the paramagnetic impurity has entered the lattice only substitutionally, as confirmed by the single crystal rotations. The spin Hamiltonian parameters calculated from the spectra are g parallel = 1.9356, g perpendicular = 1.9764, A parallel = 200.9 G and A perpendicular = 76.5 G. The optical absorption spectrum exhibits three bands (800, 670 and 340 nm) suggesting the C4v symmetry and the optical parameters evaluated are Dq = 1492, Ds = -3854 and Dt = 186 cm(-1).     

2‐Arylethenyl‐2′‐arylethynyl sulfones: A potential source for some spiroheterocycles

The double Michael addition of dimethyl malonate to 2‐arylethenyl‐2′‐arylethynyl sulfones (3) resulted in 3,5‐diaryl‐5,6‐dihydro‐4,4‐dimethoxycarbonyl‐1‐thiin‐1,1‐dioxides (4) . The latter on cyclocondensation with urea / thiourea / hydrazine hydrate / hydroxylamine hydrochloride gave spiroheterocycles.