stable crystalline phosphorus ylides are obtained in excellent yields from the 1:1:1 addition reactionbetween hydantoins or thiohydantoins and dialkyl acetylenedicarboxylates in the presence oftriphenylphosphine. these phosphoranes undergo smooth intramolecular wittig reaction followedby an electrocyclic ring opening to produce dialkyl (e)-2-(2,5-dihydro-5,5-diaryl-2-thioxo-1h-imidazol-4-yl)fum...

Various motionally averaged 31P-1H, 13C-1H, 1H-1H, and 31P-13C dipolar couplings were measured for natural-abundance and unoriented phosphocholine in the L alpha phase. The couplings were obtained and assigned by a variety of advanced and partly novel two-dimensional solid-state NMR experiments. Whereas 31P-1H and 31P-13C dipolar couplings provide long-range structural constraints, geminal 1H-1...

a rapid, specific and accurate proton quantitative nuclear magnetic resonance spectroscopic (1h qnmr) and also a reversed phase derivatization hplc method have been developed to quantify a toxic, uv-visible inactive and non-volatile impurity n,n-dimethylamine hydrochloride (dma∙hcl) in metformin hydrochloride (mf∙hcl), an active pharmaceutical ingradient. the method is based on proton quantitat...

The title compound, C(13)H(14)OS, crystallizes with two independent mol-ecules in the asymmetric unit. The unit cell contains three voids of 197 Å(3), but the residual electron density (highest peak = 0.24 e Å(-3) and deepest hole = -0.18 e Å(-3)) in the difference Fourier map suggests no solvent mol-ecule occupies this void. The crystal structure is stabilized by π-π inter-actions between the ...

The thermal behavior, decomposition kinetics and mechanisms of 1-amino-1-(tetrazol-5-yldiazenyl) guanidine (tetrazene) and 2-(tetrazol-5-yldiazenyl) guanidine (MTX-1) have been investigated using DSC, TG techniques, and quantum chemical calculations. It has been found that MTX-1 is much more stable than tetrazene and MTX-1, and both of them decompose in three steps with different kinetic parame...

Tetrazoles remain a challenge to photochemists. Photolysis leads to cleavage of the tetrazolyl ring, may involve various photodegradation pathways and may produce a diversity of photoproducts, depending on the structure and conformational flexibility of the substituents and the possibility of tautomerism. If the photochemistry of tetrazoles is considered within the frame of synthetic applicatio...

We report here the first study of the protonated, neutral form of tetrazoles as anion binding functional groups. Our studies reveal them to be capable of binding anions with extremely high potency in polar solutions. In studying carboxylic acid-containing congeners, we find a remarkable discrepancy: a strictly analogous acid-containing host binds anions > or = 50,000-fold more weakly than the t...

Aminotetrazole compounds have become attractive ingredients in gas generating compositions, solid rocket propellants, and green pyrotechnics. Therefore, a fundamental understanding of their thermal decomposition mechanisms and thermodynamics is of great interest. In this study, the specular reflection isopotential searching method was used to investigate the unimolecular decomposition mechanism...

A concise two step synthesis of tetrazole containing macrocycles from readily accessible starting materials is presented. The first step comprises a chemoselective amidation of amino acid derived isocyanocarboxylicacid esters with unprotected symmetrical diamines to afford diverse α-isocyano-ω-amines. In the second step, the α-isocyano-ω-amines undergo an Ugi tetrazole reaction to close the mac...