Synthesis of novel spiro-condensed 2-amino-4H-pyrans based on 1,2-benzoxathiin-4(3H)-one 2,2-dioxide

Chemistry of Heterocyclic Compounds - A series of new spiro-condensed 2-amino-4H-pyrans were synthesized by three-component interaction of 1,2-benzoxathiin-4(3H)-one 2,2-dioxide, malononitrile, and...     

Synthesis of 1-methyl-7-(trifluoromethyl)-1H-pyrido[2,3-c][1,2]thiazin-4(3H)-one 2,2-dioxide

The reaction of methyl 2-bromo-6-(trifluoromethyl)-3-pyridinecarboxylate ( 1 ) with methanesulfonamide gave methyl 2-[(methylsulfonyl)amino]-6-(trifluoromethyl)-3-pyridine-carboxylate ( 2 ). Alkylation of compound 2 with methyl iodide followed by cyclization of the resulting methyl 2-[methyl(methylsulfonyl)amino]-6-(trifluoromethyl)-3-pyridinecarboxylate ( 3 ) yielded 1-methyl-7-(trifluoromethyl)-1H-pyrido[2,3-c][1,2]thiazin-4(3H)-one 2,2-dioxide ( 4 ). The reaction of compound 4 with α,2,4-trichlorotoluene, methyl bromopropionate, methyl iodide, 3-trifluoromethylphenyl isocyanate, phenyl isocyanate and 2,4-dichloro-5-(2-propynyloxy)phenyl isothiocyanate gave, respectively, 4-[(2,4-dichlorophenyl)methoxy]-1-methyl-7-(trifluoromethyl)-1H-pyrido[2,3-c][1,2]thiazine 2,2-dioxide ( 5 ), methyl 2-[[1-methyl-2,2-dioxido-7-(trifluoromethyl)-1H-pyrido[2,3-c][1,2]thiazin-4-yl]oxy]propanoate ( 6 ), 1,3,3-trimethyl-7-(trifluoromethyl)-1H-pyrido[2,3-c][1,2]thiazin-4(3H)-one 2,2-dioxide ( 7 ), 4-hydroxy-1-methyl-7-(trifluoromethyl)-N-[3-(trifluoromethyl)phenyl]-1H-pyrido[2,3-c][1,2]thiazine-3-carboxamide 2,2-dioxide ( 8 ), 4-hydroxy-1-methyl-7-(trifluoromethyl)-N-phenyl-1H-pyrido[2,3-c][1,2]thiazine-3-carboxamide 2,2-dioxide ( 9 ) and N-[2,4-dichloro-5-(2-propynyloxy)phenyl]-4-hydroxy-1-methyl-7-(trifluoromethyl)-1H-pyrido[2,3-c][1,2] thiazine-3-carboxamide 2,2-dioxide ( 10 ).     

2,2'-二取代双[3-芳基喹唑啉-4(3H)-酮]的合成

研究了多米诺骨牌反应合成2,2'-二取代双[3-芳基喹唑啉-4(3H)-酮]衍生物的方法.该方法应用膦亚胺1与芳基异氰酸酯的氮杂Wittig反应得到碳二亚胺2,接着与二酚在碳酸钾存在下反应,合成了28个未见文献报道的双喹唑啉酮衍生物4.所得产物4的结构经IR,1HNMR,MS和元素分析测定,并且采用X射线衍射分析方法进一步确证了化合物4z的结构.     

Synthesis of 2H-1,4-thiazin-3(4H)-one 1-oxide and 2H-1,4-thiazin-3-(4H)-one 1,1-dioxide,structural analogs of uracil

The synthesis of 1,4-thiazine 1-oxide and 1,1-dioxide analogs of the antibiotic emimycin is described. Reaction of methylthioglycolate with 1-bromo-2,2-diethoxyethane gave methyl (2,2-diethoxyethylthio)acetate ( 2 ). Treatment of 2 with methanolic ammonia followed by cyclization furnished 2H-1,4-thiazin-3(4H)-one ( 5 ). Oxidation of 5 with m-chloroperoxybenzoic acid converted it to 2H-1,4-thiazin-3(4H)-one 1-oxide ( 6 ). Oxidation of 2 with potassium permanganate, followed by treatment with methanolic ammonia, and cyclization gave 2H-1,4-thiazin-3(4H)-one 1,1-dioxide.     

Synthesis and structural investigation of new isothiochromen-4-one 2,2-dioxide derivatives

This article presents a combined experimental and computational study of novel isothiochromene 2,2-dioxide derivatives, which were synthesized by the electrophilic substitution reactions. The compounds have been studied by NMR, IR spectroscopy and single-crystal X-ray analysis. According to X-ray diffraction data, the six-membered ring of 6 adopts a distorted half-chair conformation, but in case of compounds 7 and 8, we have a twist-boat conformation of the six-membered ring with deviation of the S1 and C8 atoms from the mean plane of the remaining atoms of the ring, respectively. Results of quantum-chemical calculations of possible isomers and tautomers of the isolated oxime 8 and azo compounds 10 at the B3LYP/aug-cc-pVDZ level indicate that the oxime-oxo tautomer (8a) is more stable than the nitroso-hydroxy tautomer (8b) in agreement with the crystal data and that the keto tautomer (II) is more stable than the hydroxyl tautomer (I) and zwitterion tautomer (III), because of a strong intramolecular hydrogen bond N–H···O.

     

Synthesis and Antifungal Activity of Novel Quinazolin-4(3H)-one Derivatives

A novel group of 6-iodoquinazolin-4(3H)-one derivatives was prepared starting from 6-iodo-2-ethoxy-4H-3,1-benzoxazin-4-one (3) via action of various nitrogen nucleophiles such as primary and secondary amines, hydrazine hydrate, and its derivatives. The 3-amino-2-hydrazinyl-6-iodoquinazolin-4(3H)-one (15) was used as a key starting material to prepare new heterocyclic compounds. The structures of all synthesized compounds were inferred from the infrared, mass spectral, and ¹H NMR spectral data as well as elemental analysis. The fungicidal activities of the target compounds were preliminarily evaluated.     

De novo synthesis of 2,2-bis(dimethylamino)-3-alkyl or benzyl 2,3-dihydroquinazolin-4(1H)-one compounds

A new versatile and efficient strategy for the synthesis of 2,2-bis(dimethylamino)-3-alkyl or benzyl 2,3-dihydroquinazoline-4(1H)-one compounds has been developed by one-pot multicomponent reaction with isatoic anhydride, amines followed by in situ-generated Vilsmeier reagent. The reaction has also been studied with different amines and solvents.     

A novel synthesis and transformations of isothiochroman 2,2-dioxide

A convenient synthesis of isothiochromen-4-one 2,2-dioxide was carried out via cyclisation of o-cyanobenzyl thioacetate by a Thorpe reaction. The reactions of isothiochromen-4-one 2,2-dioxide with nitrogen-containing nucleophilic reagents have been investigated.     

3-亚甲基异苯并呋喃-1(3H)-酮的合成

以邻甲基苯甲酸甲酯为原料,经过自由基溴代,Wittig反应,酯水解反应,得到邻乙烯基苯甲酸;随后发生环氧化反应,环合反应得到3-羟甲基异苯并呋喃-1(3H)-酮;再发生亲核取代和消除反应合成了3-亚甲基异苯并呋喃-1(3H)-酮。目标产物在空气中长期放置没有发生二聚。化合物结构用1H NMR、13C NMR和IR表征。     

Synthesis of 3-methylquinazolin-4(3H)-one derivatives

Oxidation of 3-methyl-2-sulfanylquinazolin-4(3H)-one with chlorine dioxide under different conditions gave 2,2??-disulfanediylbis[3-methylquinazolin-4(3H)-one], 3-methyl-4-oxo-3,4-dihydroquinazoline-2-sulfonic acid, 3-methylquinazoline-2,4(1H,3H)-dione, 6-chloro-3-methylquinazoline-2,4(1H,3H)-dione, and N,N-diethyl-3-methyl-4-oxo-3,4-dihydroquinazoline-2-sulfonamide.     

5-(1-Alkenyl)-1, 3, 4-oxadiazol-2(3H)-one

3-(2-alkenoyl)-thiocarbazic acid O-methyl esters 1 are desulfurated by bromine and the unknown intermediates are transformed by alkali to 5-(1-alkenyl)-1, 3, 4-oxadiazol-2(3H)-ones ( 2 ). This type of oxadiazolone substitution is not realizable by the common ring closure of hydrazides with phosgene due to pyrazolidinone ring closure of unsaturated acids with hydrazine.     

6-甲基-4-(3-三氟甲基苯基)-3(2H)-哒嗪酮的合成与生物活性研究

在对3-三氟甲基-1,1'-联苯类衍生物类化合物进行CoMFA计算的基础上,设计合成了化合物6-甲基-4-(3-三氟甲基苯基)-3(2H)-哒嗪酮(T-1),分别采用小杯法、浮萍法和盆栽法对其除草活性进行了较详细的研究,发现化合物T-1具有很好的白化活性和除草效果.研究了T-1的合成路线,实施了三条完全不同的路线进行合成,比较了三条路线的优缺点.     

A solid-phase synthetic method for 3,4-dihydro-1H-2,1-benzothiazin-4-one 2,2-dioxide derivatives

Utilizing polymer-bound anthranilic acid derivatives, we were able to obtain 3,4-dihydro-1H-2,1-benzothiazine-4-one 2,2-dioxide derivatives through N-methanesulfonylation by use of sulfonyl chloride, sulfonic acid, or sodium sulfonate, N-alkylation under Mitsunobu condition, and the cyclative cleavage in 8-52% five-step overall isolated yields and 91-99% purities from Wang resin. The reactions on solid phase were monitored by on-bead ATR-FTIR spectroscopic method and checked by help of solution-phase model experiments.     

Tilcotil® Studies [3+2] additions with isothiazol-3(2H)-one 1,1-dioxide

Derivatives of isothiazol-3(2H)-one 1,1-dioxide react regiospecifically with 1,3-dipolar agents. The main regiocontrolling factor is ascertained to be the C?O group of the dipolarophile. The topology of the adducts is also in general agreement with predictions based on perturbation theory. Several adducts can be aromatized to heterocyclic equivalents of saccharin, and may then be elaborated into structural analogs of tenoxicam (Tilcotil® and piroxicam (Feldene®)).