88381-44-6

Usage

Chemical Properties

Light Yellow Solid

InChI:InChI=1/C4H6N2O3S/c7-4(8)3-1-10-2-6(3)5-9/h3H,1-2H2,(H,7,8)

Upstream product

• 80-11-5 N-methyl-N-nitrosotoluene-p-sulfonamide 
• 444-27-9 (RS)-4-thiazolidinecarboxylic acid 
• 34592-47-7 L-thioproline 

Downstream Products

• 53375-56-7 (R or S)-3-nitroso-thiazolidine-4-carboxylic acid 2-methoxy-4-nitro-phenyl ester 

Relevant academic research and scientific papers

Spectroscopic and theoretical investigation of the conformational space of a pyrazolo-thiazole precursor of extended dipole diazafulvenium methide intermediates

The structure, preferred conformers and vibrational spectra of the pyrazolo-thiazole precursor of extended dipole diazafulvenium methide intermediates, dimethyl 2,2-dioxo-1H,3H-pyrazolo[1,5-c][1,3]thiazole-6,7-dicarboxylate (DPTD) were investigated in low-temperature noble gas matrices (Ar, Xe), low temperature neat amorphous and crystalline phases and in KBr pellet (crystal and melted phases) by infrared spectroscopy, supported by quantum chemical calculations. Two types of conformers were observed spectroscopically in the matrices and in the neat amorphous solid resulting from fast condensation of the vapour of the compound onto the cold (20 K) substrate of the cryostat. These conformers correspond to the two pairs of nearly degenerated structures exhibiting skew/cis (conformers S′C and SC′) and gauche/trans (conformers G′T and GT′) arrangements of the N{double bond, long}C-C{double bond, long}O/C{double bond, long}C-C{double bond, long}O moieties. In the crystalline phase, the vibrational signature of the compound indicates that it exists in a skew/cis arrangement. After melting of the crystal, a conformational mixture is formed, where both skew/cis and gauche/trans forms exist in equilibrium and, with all probability, also conformer G′C′. This latter conformer cannot exist in the low temperature matrices and amorphous state, in view of the very low energy barrier that separates this form from the lower energy SC′ conformer, which can be easily surpassed during deposition of the compound (conformational cooling).

Cycloadditions to pyrrolo[1,2-c]thiazoles and pyrazolo[1,5-c]thiazoles

The pyrrolo[1,2-c]thiazole generated by dehydration of dimethyl 5-methyl-1H,3H-pyrrolo[1,2-c]thiazole-6,7-dicarboxylate 2-oxide acts as a thiocarbonyl ylide in its cycloaddition to electron deficient alkenes but as an azomethine ylide with electron deficient alkynes. The analogous pyrazolo[ 1,5-c]thiazole, generated similarly, acts as a thiocarbonyl ylide with both types of dipolarophile. This behaviour is partially explained by Frontier MO theory. (C) 2000 Elsevier Science Ltd.

Azafulvenium methides: New extended dipolar systems

The transient 8π 1,7-dipolar azafulvenium methides 5 and 8 undergo sigmatropic [1,8] H shifts and the acyl derivatives 12 electrocyclise to give novel pyrrolooxazines 13; the related diazafulvenium methide 15 can be intercepted in 8π + 2π cycloadditions with silylated acetylenes.

Reactivity of Nucleophilic Nitrogen Compounds towards the Nitroso Group

We discuss the reactivity of 43 nucleophilic nitrogen compounds towards the nitroso group of N-methyl-N-nitrosotoluene-p-sulfonamide (MNTS), and in some cases with alkyl nitrites.The series of nucleophiles considered is structurally very varied, includes members exhibiting the alpha effect, and covers 8 pKa units and a range of reactivities of almost five orders of magnitude.The values of solvent isotope effects and activation parameters have been measured and throw light on the structure of the transition states involved.Reactivities do not correlate well with thebasicity of the nucleophile, largely owing to the behaviour of primary amines, ammonia and nucleophiles with an alpha effect.Application of the curve crossing model suggests a relationship with vertical ionization potentials.The relationship with Ritchie's N+ scale is discussed, and interesting correlations with the reactivities of the same nucleophiles in various other chemical processes are noted.

Kinetics and Mechanism of the Nitrosation of Thioproline: Evidence of the Existence of Two Reaction Paths

The kinetics of N-nitrosation of thioproline have been studied under a variety of experimental conditions.The experimental rate equation obtained in the absence of nucleophiles suggests that under these conditions nitrosation initially takes place at the sulphur atom, the nitroso group subsequently being transferred to the nitrogen atom.The fact that a primary isotope effect and general base catalysis are observed, together with the experimental rate equation, implies that the rearrangement is intramolecular, and that the rate-controlling step is the loss of a proton from the nitrogen atom of the S-nitrosated intermediate.Cl-, Br-, SCN-, and thiourea all catalyse the reaction via the formation of the corresponding nitrosyl compounds, which react directly with the unprotonated thioproline nitrogen atom in both the negatively charged and neutral forms of the amino acid.The observed rate constants for these reactions are discussed in terms of the nature of the nitrosating agent and the substrate.In the case of Br- and Cl- the plot of reaction rate against concentration of catalyst levels off at high values of the latter, showing that the protonated N-nitrosamine intermediate is in the steady state.The characteristics of the curve, which provide a measure of the susceptibility of the nitrosamine to nucleophiles, show that this is much less than that of aromatic amines of similar basicity.