Alan B. Brown

Dithiocarbamate salts: biological activity, preparation, and utility in organic synthesis

The review includes synthetic methodologies of dithiocarbamic acid salts, their S-substituted derivatives, and nano particles (NPs) in their synthesis. This review also deals with the utility of dithiocarbamates in synthesis of: (a) heterocycles, (b) some organic reagents and (c) NPs.

Thieno[2,3-d]pyrimidines in the Synthesis of Antitumor and Antioxidant Agents

Dimethyl acetylenedicarboxylate, ethyl propiolate, and E‐dibenzoylethylene react with thienopyrimidines (cyclo‐pentyl, ‐hexyl, and ‐heptyl) derivatives to form thiazolo[3,2‐a]thieno‐[2,3‐d]pyrimidin‐2‐ylidene) acetates, thieno[2,3‐d]pyrimidin‐2‐ylthioacrylates, and thieno[2′,3′:4,5]pyrimido[2,1‐b][1,3]thiazin‐6‐ones, respectively. Reactions proceed via cyclization and thio‐addition processes. Some derivatives of thienopyrimidines showed high inhibition of Hep‐G2 cell growth compared with the growth of untreated control cells. However, the fused heptyl of thienopyrimidothiazines indicates a promising specific antitumor agent against Hep‐G2 cells with IC50 < 20 μM.

Reaction of ethyl 2-cyano-3,3-bis(methylthio)acrylate with amidrazones; synthesis of new mercapto pyrazoles and NMR investigation

2-Cyano-3,3-bis(methylthio)acrylate and N-arylbenzamidrazones reacted together to give mercapto pyrazole derivatives. The structure of the obtained products was proved by IR, mass, and NMR spectra and elemental analyses. Two-dimensional NMR spectroscopy was used to differentiate between other possible alternative structures. The reaction mechanism is also discussed. GRAPHICAL ABSTRACT

Unusual reactivity of 2,3-diphenylcyclopropenone towards N-imidoyl thioureas; facile synthesis of 3-aryl-2,5,6-triphenylpyrimidin-4(3H)-one (PART III)

2,3-Diphenylcyclopropenone (1) reacts with N-imidoylthioureas 2a–e to form the pyrimidin-4(3H)-ones 5a–e. The reaction mechanism can be described as due to stepwise addition accompanied by elimination of phenyl isothiocyanate.

Reaction of arylidenehydrazono-4-aryl-2,3-dihydrothiazole-5-carbonitriles with diethyl acetylenedicarboxylate. Synthesis of (Z)-ethyl 2-[((Z)-2-(E)-arylidenehydrazono)-4-oxo-thiazolidine-5-ylidene]acetates. NMR investigation

(Z)-Ethyl 2-[((Z)-2-(E)-arylidenehydrazono)-4-oxo-thiazolidine-5-ylidene]acetates were synthesized by three different methods: (a) reaction of arylidenehydrazono-4-aryl-2,3-dihydrothiazole-5-carbonitriles with diethyl acetylenedicarboxylate (DEAD) in acetic acid with prolonged reflux, (b) reaction between thiosemicarbazones, 2-arylidenemalononitriles and DEAD under conventional conditions or microwave irradiation, (c) one-pot three-component reaction of thiosemicarbazone derivatives, ylidene and DEAD. The thiazolinone adducts were obtained in good to excellent yields. NMR of the obtained products was investigated. GRAPHICAL ABSTRACT

Dichotomous Reactivity of PCl5 and PBr5 Toward Cyclic Ketones: A One-Step Preparation of 1,1,2-Trichlorocycloalkanes

Abstract Small-ring cyclic ketones react with excess PCl5 in CCl4 (reflux, 1-3 d) to give the corresponding 1,1,2-trichlorocycloalkanes, but react with PBr5 to give ketones brominated in the α-positions.

Synthesis of pyrano[3,2- c ]quinoline-4-carboxylates and 2-(4-oxo-1,4-dihydroquinolin-3-yl)fumarates

Reaction of equimolar amounts of 2,4(1H,3H)-quinolinediones and diethyl acetylenedicarboxylate in absolute ethanol, containing catalytic triethylamine, gave ethyl 5,6-dihydro-2,5-dioxo-6,9-disubstituted-2H-pyrano[3,2-c]quinoline-4-carboxylates in good yields. In a different manner, reaction of two equivalents of dialkyl acetylenedicarboxylates with one equivalent of 2,4(1H,3H)-quinolinediones afforded dialkyl 2(4-oxo-1,4-dihydroquinolin-3-yl)fumarates in good yields. The structures of the products were elucidated by 1H NMR, 13C NMR, two-dimensional NMR, IR, mass spectra and elemental analyses.Graphical Abstract

Synthesis of spiro[indoline-3,4′-pyrano[3,2-c]quinolone]-3′-carbonitriles

Quinoline-2,4-diones reacted with 2-(2-oxo-1,2-dihydroindol-3-ylidene)malononitrile in pyridine to give 2′-amino-2,5′-dioxo-5′,6′-dihydrospiro(indoline-3,4′-pyrano[3,2-c]quinoline)-3′-carbonitriles in good to excellent yields. The structures of all new products were proven using one- and two-dimensional NMR, IR, and mass spectral data, and in five cases X-ray structural analyses. The possible mechanism for the reaction is also discussed.Graphical abstract

Mini Review of Sulfur Heterocyclization from π-Electron Deficient Quinones via Charge-Transfer Interaction

Abstract This survey is mainly concerned with selected reactions of 2,3-dichloro-1,4-naphthoquinone (DHNQ), 3,4,5,6-tetrachloro-1,2-benzoquinone (o-CHL), 2,3,5,6-tetrachloro-1,4-benzoquinone (p-CHL), and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as π-deficient quinones that are used or offer potential use for sulfur heterocyclic synthesis. Reaction of various donors with the π-deficient quinones are studied, especially those via charge-transfer complex formation. GRAPHICAL ABSTRACT

Chapter Five - Heterocycles from the Reaction of Thione Groups with Acetylenic Bonds

Abstract This chapter discusses reactions between the thione and alkyne functional groups, subdivided into internal (intramolecular) and external (intermolecular) reactions. Many such reactions are intramolecular; surprisingly, few involve addition of thione groups to benzyne. Selectivity of additions varies from one substrate to another, and is affected by solvent polarity. The synthesized heterocycles range from four- to eight-membered ring systems with one to three heteroatoms.