Identification of New, Odor-Active Thiocarbamates in Cress Extracts and Structure−Activity Studies on Synthesized Homologues

Abstract

New, odorant nitrogen- and sulfur-containing compounds are identified in cress extracts. Cress belongs to the botanical order Brassicales and produces glucosinolates, which are important precursors of nitrogen- and sulfur-containing compounds. Those compounds often present low perception thresholds and various olfactive notes and are thus of interest to the flavor and fragrance chemistry. When the study of organonitrogen and organosulfur compounds is undertaken, Brassicale extracts are one of the matrices of choice. Cress extracts were studied by analytical (GC-MS, GC-FPD) and chemical (fractionation) means to identify new interesting odorant compounds. Two compounds that have never been reported in cress extracts, containing both nitrogen and sulfur, were discovered: N-benzyl O-ethyl thiocarbamate and N-phenethyl O-ethyl thiocarbamate. These two molecules being of organoleptic interest, their homologues were synthesized and submitted to organoleptic tests (static and GC-sniffing). Their odors evolve from garlic and onion over green, mushroom- and cress-like to fresh, spearmint-like. This paper presents the origin, chemical synthesis, and organoleptic properties of a series of O-alkyl thiocarbamates.

Synthesis and polymerization of styrene monomer carrying isothiocyanate moiety and its copolymerization with HEMA based on chemo-selectivity to nucleophiles

“…Stirred for 6 h at 25 °C, the mixture was evaporated and purified by silica gel column chromatography. The compound characterization data of thiocarbamate 6 was identical to the one previously reported …”

“…To make sure the reactivity of benzyl isothiocyanate toward alcohol, model reaction was performed. The reactions of benzyl isothiocyanate and alcohol (methanol, ethanol, 1‐propanol) were reported in a harsh condition; however we investigated the reactivity under mild condition using benzyl isothiocyanate and 1‐propanol (Table ). To investigate the stability of isothiocyanate in alcohol, benzyl isothiocyanate was reacted with 1 equiv of 1‐propanol in THF at 25 °C for 6 h. No reaction was observed by 1 H NMR and the benzyl isothiocyanate was recovered in 97%.…”

“…In addition, the reaction might have to do with the phenomenon that copolymers which contained HEMA part over 50 mol % (entry 2 and 3) became gel by standing at room temperature for several hours. Because the polymer with high HEMA content have a high local concentration of alcohol moiety enough to react with isothiocyanate even in the absence of DBU …”

Ultra-Trace Determination of Methyl Carbamate and Ethyl Carbamate in Local Wines by GC-FID Following Pre concentration with C18-SPE

“…Some methods still include an additional extraction cleanup step 4,15 . Ethyl carbamate detection is usually performed by mass spectrometry [1][2][3][4]7,8,15 , either on electron or chemical ionization 23,24 . Other detection techniques such as Hall electrolytic conductivity detection and thermal energy analyzer in nitrogen detection have also been applied 25,26 .…”

S-Allyl Thiocarbamates from Allylic Alcohols by in situ [3,3]-Sigmatropic Rearrangement of a Thiocarbonyldiimidazole Adduct

“…5,7 They have been reported to have hypnotic 3 and tuberculostatic activity 3 and can be employed in flavour and fragrance chemistry. 8 S-Alkyl thiocarbamates are most known for their use as commercial herbicides. 1,4,9 Allylic thiocarbamates have been used as terminators in radical-based cyclisation reactions.…”