Synthesis of tetronic acid enamine. Dienamine derivatives from 3-(2H)furanones

The synthesis of 5-aryl (or alkyl) aminomethylene-3-(1-amino or 1-alkylaminoethylidene)-2,4-dioxo-(3H,5H)furans and 5-arylaminomethylene-3-(1-hydroxyethylidene)-2,4-dioxo-(3H,5H)furans (new 3-acetyltetronic acid derivatives) are described. The stereochemistry of these compounds from the ¹H nmr data is discussed.     

3-羟基-4-甲基-5-乙基-2(5H)-呋喃酮的合成

报道了以草酸二乙酯为原料,制备具有焦糖香味的香料化合物3-羟基-4-甲基-5-乙基-2(5H)-呋喃酮的方法:首先乙基溴化镁与草酸二乙酯通过格氏反应,以约50%产率生成2-氧代丁酸乙酯,然后其在碳酸钾的作用下发生缩合反应,以约94%产率得到3-羟基-4-甲基-5-乙基-5-乙氧羰基-2(5H)-呋喃酮,再通过水解、脱羧反应,得到3-羟基-4-甲基-5-乙基-2(5H)-呋喃酮.路线总收率约36%.     

4-羟基-2(1H)-吡啶酮-3-甲酰胺类冬青生菌素类似物的合成与生物活性

以反式-4-羟基肉桂酸为起始原料,经乙酰化、酰基叠氮、curtius重排、加成和环合等6步反应合成了4-羟基-2(1 H)-吡啶酮-3-甲酰胺类冬青生菌素类似物,总收率17%.随后用滤纸片扩散法对该化合物的抑菌性能进行了初步研究.实验表明,该化合物对于白色念珠菌具有较好的抑制作用,对于酵母菌抑制作用较弱,对大肠杆菌和金黄色葡萄球菌基本无抑制作用.     

Synthesis and antimicrobial activity of some derivatives of (7-hydroxy-2-oxo-2H-chromen-4-yl)-acetic acid hydrazide

(7-Hydroxy-2-oxo-2H-chromen-4-yl)-acetic acid hydrazide (2) was prepared from (7-hydroxy-2-oxo-2H-chromen-4-yl)-acetic acid ethyl ester (1) and 100% hydrazine hydrate. Compound 2, is the key intermediate for the synthesis of several series of new compounds such as Schiff's bases 3a-l, formic acid N'-[2-(7-hydroxy-2-oxo-2H- chromen-4-yl)acetyl] hydrazide (4), acetic acid N'-[2-(7-hydroxy-2-oxo-2H-chromen-4- yl)-acetyl] hydrazide (5), (7-hydroxy-2-oxo-2H-chromen-4-yl)-acetic acid N'-[2-(4- hydroxy-2-oxo-2H-chromen-3-yl)-2-oxoethyl] hydrazide (6), 4-phenyl-1-(7-hydroxy-2- oxo-2H-chromen- 4-acetyl) thiosemicarbazide (7), ethyl 3-{2-[2-(7-hydroxy-2-oxo-2H- chromen-4-yl)-acetyl]hydrazono}butanoate (8), (7-hydroxy-2-oxo-2H-chromen-4-yl)- acetic acid N'-[(4-trifluoromethylphenylimino)methyl] hydrazide (9) and (7-hydroxy-2- oxo-2H-chromen-4-yl)acetic acid N'-[(2,3,4-trifluorophenylimino)-methyl] hydrazide (10). Cyclo- condensation of compound 2 with pentane-2,4-dione gave 4-[2-(3,5- dimethyl-1H-pyrazol-1-yl)-2-oxoethyl]-7-hydroxy-2H-chromen-2-one (11), while with carbon disulfide it afforded 7-hydroxy-4-[(5-mercapto-1,3,4-oxadiazol-2-yl)methyl]-2H- chromen-2-one (12) and with potassium isothiocyanate it gave 7-hydroxy-4-[(5- mercapto-4H-1,2,4-triazol-3-yl)methyl]-2H-chromen-2-one (14). Compound 7 was cyclized to afford 2-(7-hydroxy-2-oxo-2H-chromen-4-yl)-N -(4-oxo-2-phenylimino- thiazolidin-3-yl) acetamide (15).     

Synthesis of 1,6-dihydro-5-hydroxy-6-oxo-3-(trifluoromethyl)-4-pyridazinecarboxylates

The reaction of 2-(alkylamino)-3-(trifluoroacetyl)butenedioates 2a-b with alkyl and aryl hydrazines in ether provides 1,6-dihydro-6-oxo-3-(trifluoromethyl)-4-pyridazinecarboxylates as their alkylamine salts 3a-g . The structures of these products are substantiated using 2D nmr and ¹⁵N nmr techniques.     

2,5-二甲基-4-羟基-3(2H)呋喃酮的合成

以乙酰丙酮(1)为原料，经电解氧化偶联，Paal-Knorr闭环，Baeyer-Villiger氧化，水解等步骤，合成了一种重要的杂环香料，2,5-二甲基-4-羟基-3(2H)呋喃酮(6)。     

Synthesis of new 4(3H)-quinazolinone derivatives using 5(4H)-oxazolones

New derivatives of 5(4H)-quinazolinone containing 2-imidazolin-5-one rings have been prepared from 5(4H)-oxazolone derivatives.     

Synthesis of some isomeric 4-ethoxycarbonyl-3-and 5-(1- and 2-hydroxyalkyl)-1,3- and 1,5-dimethylpyrazoles from 3-(2H)furanones and 2,3-dihydro-4-pyrones

The title compounds were prepared by reaction of 3-(2H)furanones and 2,3-dihydro-4-pyrones with methylhydrazine or alternatively by methylation of the corresponding N-unsubstituted pyrazoles. ¹³C and ¹H nmr were used to assign the isomeric 3-methyl or 5-methyl structures.     

Synthesis of isoxazolo[4,5-d]pyridazin-4(5H)-ones and 4-acyl-5-hydroxy-3(2H)-pyridazinones

The title compounds were prepared from ethyl 5-acyl- or 5-(1-hydroxyethenyl)isoxazole-4-carboxylates which in turn were prepared from ethyl 3-methylamino-2-butenoate or 3(2H)-furanones.     

Synthesis of 2-oxo-3-benzothiazolineacetyl chloride (7), 5-chloro-2-oxo-3-benzothiazolineacetyl chloride (8) and derivatives

The reaction of 2-oxo-3-benzothiazolineacetic acid ( 5 ) and the 5-chloro analogue 6 with thionyl chloride afforded the titled compounds 7 and 8 . The reaction of 7 or 8 with substituted hydrazines, amines or substituted anilines, alcohols and mercaptans furnished the hydrazides 9–14 , acetamides and acetanilides 16–21 , esters 26–30 and thiolesters 31–37 , respectively. Alternate routes for the synthesis of hydrazide 15 , acetamides and acetanilides 22–25 and thiolesters 35–36 are described. The reaction of 2-oxo-3(2H)-benzothi-azolineacetonitrile with thioacetic acid under acidic conditions afforded 2-oxo-3-benzothiazolineethanethio-amide (38).     

Synthesis of 4-norpyridoxine (3-hydroxy-5-hydroxymethyl-2-methylpyridine)

3-Hydroxy-5-hydroxymethyl-2-methylpyridine (4-norpyridoxine) has been synthesized by the heterodiene condensation of 4-methyl-5-propoxyoxazole and 5-ethoxy-2,5-dihydrofuran-2-one through the stage of 3-hydroxy-2-methylpyridine-5-carbaldehyde with reduction of the latter by NaBH₄. One of the isomeric adducts has been isolated, and its stereochemistry has been established by PMR spectroscopy.     

Synthesis and Structure (Z)-N-Aryl-2-hydroxy-4-oxo-4-phenylbut-2-enamides

Russian Journal of General Chemistry - Reactions of 5-phenyl-2,3-dihydrofuran-2,3-dione with aromatic amines in anhydrous dioxane or methyl benzoylpyruvate with aromatic amines in the presence of...     

Modification of Synthesis of 3-Chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone(MX)

Addition of chlorine to methyl 3-(dichloromethyl)-4,4-dichlorocrotonate (1), a critical procedure in the total synthesis of the title compound MX, was modified by using novel catalysts. A minor modification in the purification of MX was also described.     

Synthesis of 4,4a,5,6,7,8-hexahydro-5-hydroxy-4a-methyl-2(3H)-naphthalenone

Summary New preparative methods were developed for the synthesis of 4,4a,5,6,7,8~hexahydro-5-hydroxy-4a-methyl-2(3H)-naphtalenone (II) from 3,4,8,8a-tetrahydro-8a-methyl-1,6(2H,7H)-naphthalenedione (I).     

Synthesis of 4(3H)-quinazolinones from derivatives of methyl 2-isothiocyanatobenzoate

Ethyl N-(2-methoxycarbonylphenyl)thiocarbamate ( 2), N -(2-ethoxycarbonylphenyl)-4-methoxythiobenz-amide ( 3b ), and 2-(4-methoxyphenyl)-4H-3,1-benzothiazin-4-one ( 4a ), react with nucleophilic reagents containing at least one primary amino group to yield a variety of 2-substituted and 2,4-disubstituted 4(3H)quinazolinones, as well as some tricyclic and tetracyclic products.     

Synthesis of (S,S)-1,5-bis(4-alkyl-5-hydroxy-2-oxo-3-azapentyl)-1,5-diazacyclooctane

Crown ether derivatives have been extensively developed to provide enhanced structural recognition of substrate alkyl-ammonium cations. In particular a number of investigations of complexation of chiral alkylammonium salts by chiral crown ethers have been reported. The enantioselectivity has been applied in the chromatographic resolution of amino acid perchlorates. In general the crown ethers used in these studies have been based upon derivatives of 2, 2′-dihydroxy-1, 1′-binaphthyl1 or deriv…     

Synthesis of 4-aryl-2-hydroxy-4-oxo-2-butenoic (Aroylpyruvic) acids N-(4-Acetylaminosulfonylphenyl)amides

Methyl aroylpyruvates react with sodium 4-aminobenzenesulfonylacetamide in acetic acid to afford 4-aryl-2-hydroxy-4-oxo-2-butenoic acids N-(4-acetylaminosulfonylphenyl)amides. The latter were studied in reactions with hydrazine hydrate.     

13C and 1H NMR analysis of the nitration products of 2-amino-4-oxo-(3H)-5-trifluoromethylquinazoline and 2-amino-4-oxo-(3H)-5-fluoroquinazoline

Nitration of 2-amino-4-oxo-(3H)-5-trifluoromethylquinazoline is shown to occur exclusively at C⁶ as determined from an analysis of long range ¹H and ¹⁹F scalar couplings to ring carbons. Nitration of 2-amino-4-oxo-(3H)-5-fluoroquinazoline is found to occur both at C⁶ and C⁸ as evident from an analysis of the ¹⁹F and ¹H couplings of the ring protons.     

4-hydroxy-2-quinolones. 18. Synthesis and antithyroid activity of 1-R-2-oxo-3-(4-oxo-3H-quinazolin-2-yl)-4-hydroxyquinolines

Preparative methods for the synthesis of 1-R-2-oxo-3-(4-oxo-3H-quinazolin-2-yl)-4-hydroxyquinolines based on ethyl esters or nitrites of 1-R-2-oxo-4-hydroxyqidnoline-3-carboxylic acids and anthranilamide or ethyl anthranilate correspondingly were proposed. The antithyroid activity of the compounds synthesized was studied.For Communication 17, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1223–1226, September, 1993.     

Synthesis and Crystal Structure of Ethyl 4-（2-Chloro-4-fluorophenyl）-6-hydroxy-3-oxo-1,3-dihydro-5-isobenzofurancarboxylate

The crystal structure of the title compound(C17H12ClFO5,Mr=350.72) was determined by single-crystal X-ray diffraction.The crystal belongs to monoclinic,space group P21/c,with a=7.693(1),b=15.767(1),c=12.986(1),β=97.23(1)°,V=1562.6(2)3,Z=4,Dc= 1.491 g/cm3,λ(MoKα)=0.71073,F(000)=720,μ(MoKα)=0.280 mm-1,R=0.0563 and wR=0.1674.A total of 3592 unique reflections were collected,of which 2462 with Ⅰ2σ(Ⅰ) were observed.Five-membered lactone rings and hydroxyl-substituted phenyl rings are approximately coplanar with their dihedral angle of 4.1°.The dihedral angle between two different phenyl rings is 71.3°.To our interest,intramolecular O(1)-H(1)···O(4) hydrogen bonds could be found in each molecule.Intramolecular hydrogen bonds and intermolecular van der Waals force contribute to the stability of the structure.