Synthesis of New Substituted 2,3-Dihydro-1,4-dioxin-2-ones and 1,4-Dioxan-2-ones

3-Alkyl-6-methyl-2,3-dihydro-1,4-dioxin-2-ones reacted with acetyl chloride in the presence of zinc(II) chloride to give 5-acetyl-3-alkyl-6-methyl-2,3-dihydro-1,4-dioxin-2-ones. Oxidation of the latter with hydrogen peroxide in formic acid, followed by treatment with magnesium bromide, afforded 3-alkyl-6-methyl-1,4-dioxane-2,5-diones. Chlorination of 6-hydroxymethyl-1,4-dioxan-2-ones with thionyl chloride and subsequent dehydrochlorination led to formation of 6-methylene-1,4-dioxan-2-ones.     

Synthesis of C(2)Halomethyl Substituted Derivatives of 2,3-Dihydro-1,3-benzoxaz-4-ones

In the pursuit of biologically active compounds we required as a key intermediate 2,3-dihydro- 1,3-benzoxaz-bones having a halomethylene moiety at C(2), i.e. 3 (R₂ = H or alkyl, R₃ = CH₂X). The standard procedure for the preparation of this class of compounds is the condensation of salicylamide derivatives 1 with the proper aldehyde^1-5 and ketone^5,6. Usually, hydrochloric acid or sulphuric acid is used as catalyst and the water formed is cocornmittently removed using a dehydrating agent or by azeotropic destillation⁷. These procedures did not serve our purpose as the required α-substituted aldehyde or ketone as such is unstable under the conditions employed. Here we report that employment of acetals and ketals 2 affords the desired compound 3; yields are appreciable when the proper reaction conditions are used.     

New Dipyrrinonols Derived from 2,3-Dihydro-1H-pyrrol-3-ones

Summary. The reaction of 2-aminomethylene-2,3-dihydropyrrol-3(1H)-ones with ethyl bromoacetate, chloroacetonitrile, or dilute HCl gave rise to a series of methine dyes, namely 1-aryl-2-[3-hydroxy-1-aryl-4,5-diphenyl-1H-pyrrol-2-yl]methylene-4,5-diphenyl-2,3-dihydropyrrol-3(1H)-ones.     

2,3-二氢-1,4-苯并噁嗪衍生物的合成研究进展

综述了2,3-二氢-1,4-苯并噁嗪衍生物的合成研究进展,并对其发展趋势、应用前景作了进一步的展望。     

Synthesis of 5-alkynyl-2,2,6-trimethyl-1,3-dioxin-4-ones and 1,4-disubstituted-1,2,3-triazoles

Herein we report an approach to the formation of 5-alkynyl-1,3-dioxin-4-ones using Suzuki-Miyaura cross-coupling reaction of potassium alkynyltrifluoroborate salts with 2,2,6-trimethyl-5-iodo-1,3-dioxin-4-one. The resulting 5-ethynyltrimethylsilyl-1,3-dioxin-4-ones obtained through the Sonogashira reaction were further reacted in a Cu(I)-catalyzed Huisgen azide-alkyne 1,3-dipolar cycloaddition to form functionalized 1,4-disubstituted-1,2,3-triazoles in good yields, using mild conditions and ultrasonic radiation to expedite the reaction.     

Silver-Mediated Cascade Synthesis of Functionalized 1,4-Dihydro-2H-benzo-1,3-oxazin-2-ones from Carbon Dioxide

A conceptually novel catalytic domino approach is presented for the synthesis of highly functional 1,4-dihydro-2H-1,3-benzoxazine-2-one derivatives. Key to the chemoselectivity is a proper design of the precursor to override thermodynamically favored parasitic cyclization processes and empower the formation of the desired product through Thorpe–Ingold effects. The synthetic diversity of these CO₂-based heterocycles is further demonstrated, and the isolation of a reaction intermediate supports an unusual ring-expansion sequence from an α-alkylidene, five-membered cyclic carbonate to a six-membered cyclic carbamate by N-induced isomerization.     

Synthesis of 2,3-Dihydro-1-benzofuran-2-ylmethyltellanes

Russian Journal of General Chemistry - Tellurium tetrabromide readily reacted with 2-allylphenol at room temperature in acetonitrile to give previously unknown...     

One-Pot Synthesis of 2,3-Dihydro-2,3-disubstituted Benzo[g]-quinazolin-4(1H)-ones

Condensation of 2H-naphth[2,3-d][3,1] oxazin-2,4 (IH)-dione (1) with schiff bases (2) in acetic acid resulted in the formation of 2,3-dihydro-2,3-diarylbenzo[g]quinazolin-4(IH)-ones (3). Reaction of 1 with ketoanils generated in situ results in 2,3-dihydro-2,2-substituted-3-phenylbenzo[g]quinazolin-4 (IH)-ones (6) and the spiroalkanes (5). Dehydrogenation of 3 gave 2,3-diaryl benzo[g]quinazolin-4(3H)-ones (7).     

新型1,4-苯并二氮杂?-5-酮三氟乙基和环丙基取代衍生物的合成及抗肿瘤活性初探

以邻硝基苯甲酸衍生物为底物,经3或4步反应,并在第3步关环反应中使用了乙酰丙酮钼和三氟甲磺酸铜作为催化剂,合成了10个新型的1,4-苯并二氮杂?-5-酮三氟乙基和环丙基取代衍生物（4a~4f, 5a~5b, 6a~6b）,其结构经¹H NMR, ¹³C NMR和HR-MS(ESI)表征。测试了目标化合物对慢性骨髓性白血病细胞、乳腺癌、肺癌和宫颈癌等4种肿瘤细胞系的抑制活性。结果表明：化合物2-（丙-1-烯-2-基）-4-（2,2,2-三氟乙基）-1,2,3,4-四氢-5H-苯并[e][1,4]二氮杂-5-酮（4a）对慢性骨髓性白血病细胞K562的IC50可达2.6 μM;目标化合物对肺癌A549、乳腺癌MDA-MB-231和宫颈癌HeLa细胞系也表现出一定的抑制活性。     

Synthesis and Structure of 3,4-Dihydro-4-phenyl-1,5-benzodioxepin-2-ones

Baeyer-Villiger rearrangement of substituted flavanones using MCPBA affords ring-expanded products, shown by NMR spectroscopy to be the corresponding 3,4-dihydro-4-phenyl-1,5-benzodioxepin-2-ones.     

Zur Konformation von 3-Chlormethylsubstituierten 2,3-Dihydro-1,4-benzoxathiinen

The preferential conformation of some 3-substituted 1,4-benzoxathianes has been determined by means of ¹H n.m.r. spectroscopy.     

Efficacious Entry Into Substituted 5,6-Dihydro-4-Hydroxy-2H-Pyran-2-Ones and 2,3-Dihydro-4H-Pyran-4-Ones Utilizing Ketonic Dianions

Methyl acetoacetate and 2,4-pentanedione dianions were condensed with aldehydes and ketones to afford a 1,3,5-trioxygenated carboskeleton. Intramolecular cyclization of the aldol adducts delivered the title compounds in good yield.     

Synthesis of 5,6-dihydro-2H-thiins and 2,3-dihydro-1,4-oxathiins based on 1-benzylsulfonyl-1,1-dihydropolyfluoroalkan-2-ones

1-Benzylsulfonyl-1,1-dihydropolyfluoroalkan-2-ones react with phthalimidosulfenyl chloride or succinimidosulfenyl chloride to form the sulfenylated products on the active methylene group, 1-benzylsulfonyl-1-phthalimido(succinimido)thiopolyfluoroalkan-2-ones. Decomposition of the latter leads to formation of 1-benzylsulfonyl-1-thioxopolyfluoroalkan-2-ones. These compounds easily undergo the hetero Diels-Alder reaction with electron-rich 1,3-dienes as dienophiles and with electron-rich olefins as hetero-1,3-dienes. Polyfluoroalkyl substituted derivatives of six-membered sulfur-containing heterocycles, 5,6-dihydro-2H-thiins and 2,3-dihydro-1,4-oxathiins, are obtained as a result of these reactions.     

Synthesis of imidazolidin-4-ones and their conversion into 1,4-benzodiazepin-2-ones

α-Haloacetanilides Ia-e react with hexamine in ethanol giving the bisimidazolidin-4-one derivatives IIa-e, which hydrolize, in acidic media into the corresponding mono-imidazolidin-4-ones IIIa-e. The compounds IIa-d were converted into 1,4-benzodiazepin-2-ones, under different conditions and in the presence of a variety of agents. The yields were between 50 and 100%.     

Synthesis of Novel 1,4-Benzoxazine-2,3-Dicarboximides from Maleic Anhydride and Substituted Aromatic Amines

A series of novel 1,4-benzoxazine-2,3-dicarboximides starting from maleic anhydride and substituted aromatic amines were synthesized.     

新型氯化三苯基锡(1,4-二氢-2,3-二苯基四氮唑酮)配合物的合成及其性能

以三苯基氯化锡和二苯碳酰二肼为原料,在乙醇-钠中反应合成了一个新型的氯化三苯基锡(1,4-二氢-2,3-二苯基四氮唑酮)配合物（1）,其结构经FT-IR,元素分析和X-射线单晶衍射表征。结果表明：1（CCDC: 1 445 377）属单斜晶系,P21/c空间群,晶胞参数a=1.393 2(6) nm, b=1.097 3(5) nm, c=1.933 7(8) nm, β=110.219(9) ,V= 2.77 4(2) nm³, Z=4, Dc=1.498 g·cm^-3, F(000)=1 264, R₁=0.028 8, wR₂=0.064 6。中心Sn为五配位三角双锥构型。研究了1的荧光性质、热稳定性、电化学性质和体外抗癌活性。结果表明:1在100 ℃下较稳定; 1在400 nm(λ_ex=320 nm)处有弱荧光峰;c(1)=5 μg·mL^-1时,对HeLa细胞株增殖的抑制率为93.70%。