- Screening of simple carbohydrates as a renewable organocatalyst for the efficient construction of 1,3-benzoxazine scaffold
-
A convenient protocol for the two component preparation of 1,3-benzoxazines by using several protected and unprotected carbohydrate molecules as organocatalysts have been developed which is broadly applicable to condensation reaction between variety of Ma
- Y?ld?r?m, Ayhan,Kaya, Yunus,G?ker, Mustafa
-
-
- Electrochemical Intramolecular Dehydrogenative Coupling of N-Benzyl(thio)amides: A Direct and Facile Synthesis of 4H-1,3-Benzoxazines and 4H-1,3-Benzothiazines
-
The electrochemical dehydrogenative cyclization of N-benzylamides was investigated with a Pt plate anode and graphite rod cathode in an undivided cell at room temperature. The oxidative degradation of the products was suppressed successfully and 4H-1,3-benzoxazines were obtained regardless of the substituents at the benzylic position. This method also allowed for the preparation of 4H-1,3-benzothiazines.
- Yu, Hui,Jiao, Mingdong,Huang, Ruohe,Fang, Xiaowei
-
p. 2004 - 2009
(2018/11/23)
-
- High throughput mechanochemistry: Application to parallel synthesis of benzoxazines
-
We describe herein an unprecedented mechanochemical "parallel synthesis" of 3,4-dihydro-2H-benzo[e][1,3]oxazine derivatives via a one pot three component reaction. The new milling system uses a multiposition jar (variable sizes are possible), allowing for the processing of up to 12 samples simultaneously, leading to the formation of a fungicide and a building block for polymer preparation with higher throughput compared to standard milling devices.
- Martina,Rotolo,Porcheddu,Delogu,Bysouth,Cravotto,Colacino
-
supporting information
p. 551 - 554
(2018/01/19)
-
- The modified-Mannich reaction: Conversion of arylboronic acids and subsequent coupling with paraformaldehyde and amines toward the one-pot synthesis of Mannich bases and benzoxazines
-
A modified Mannich reaction has been developed for the synthesis of Mannich bases and benzoxazines via the oxidative hydroxylation of arylboronic acids and subsequent coupling with paraformaldehyde and amines in one pot. This modified Mannich reaction is easily carried out to afford the target products in good to excellent yields and tolerates a variety of functional groups.
- Liu, Juan,Yuan, Gaoqing
-
supporting information
p. 1470 - 1473
(2017/03/23)
-
- Ammonium salt catalyzed ring-opening polymerization of 1,3-benzoxazines
-
The effect of amine HCl salts as catalysts on the ring-opening polymerization (ROP) of simple 1,3-benzoxazines was investigated. The catalyst effects on the structure of the final polymer was examined and compared. The curing process for each salt-benzoxa
- Kocaarslan, Azra,Kiskan, Baris,Yagci, Yusuf
-
p. 340 - 346
(2017/07/10)
-
- Influence of substituent on equilibrium of benzoxazine synthesis from Mannich base and formaldehyde
-
N-Substituted aminomethylphenol (Mannich base) and 3,4-dihydro-2H-3- substituted 1,3-benzoxazine (benzoxazine) were synthesized from substituted phenol (p-cresol, phenol, p-chlorophenol), substituted aniline (p-toluidine, aniline, p-chloroaniline) and formaldehyde to study influence of substituent on equilibrium of benzoxazine synthesis from Mannich base and formaldehyde. 1H-NMR and charges of nitrogen and oxygen atoms illustrate effect of substituent on reactivity of Mannich base, while oxazine ring stability is characterized by differential scanning calorimetry (DSC) and C-O bond order. Equilibrium constants were tested from 50 °C to 80 °C, and the results show that substituent attached to phenol or aniline has same impact on reactivity of Mannich base; however, it has opposite influence on oxazine ring stability and equilibrium constant. Compared with the phenol-aniline system, electron-donating methyl on phenol or aniline increases the charge of nitrogen and oxygen atoms in Mannich base. When the methyl group is located at para position of phenol, oxazine ring stability increases, and the equilibrium constant climbs, whereas when the methyl group is located at the para position of aniline, oxazine ring stability decreases, the benzoxazine hydrolysis tends to happen and equilibrium constant is significantly low. the Partner Organisations 2014.
- Deng, Yuyuan,Zhang, Qin,Zhou, Qianhao,Zhang, Chengxi,Zhu, Rongqi,Gu, Yi
-
p. 18341 - 18348
(2014/09/30)
-
- Synthesis and biological activity of some 3-aryl-3,4-dihydro-2h-benz[e]-1, 3-oxazines/6-bromo-3-aryl-3,4-dihydro-2h-benz[e]-1,3-oxazines
-
N-(2-Hydroxy)-benzyl-arylamine (1) gives substantially pure 3-aryl-3,4-dihydro-2H-benz[e]-1,3-oxazines/6-bromo-3-aryl-3,4-dihydro-2H-benz[e] -1,3-oxazines (2) on cyclization with formaldehyde in methanol within 0.5-1.0 h at 65-68 C in excellent yields. Th
- Shukla, Davender Kumar,Rani, Manju,Khan, Arif Ali,Tiwari, Kavita,Gupta, Rajinder K.
-
p. 5921 - 5924
(2013/07/26)
-
- SnCl4-catalyzed aza-acetalization of aromatic aldehydes: Synthesis of aryl substituted 3,4-dihydro-2H-1,3-benzoxazines
-
Stannic tetrachloride was an efficient Lewis acid catalyst for the aza-acetalization of aromatic aldehydes with o-arylaminomethyl phenols, and a series of novel aryl substituted 3,4-dihydro-2H-1,3-benzoxazines were prepared in good yields under mild condi
- Tang, Zilong,Chen, Weiwen,Zhu, Zhonghua,Liu, Hanwen
-
p. 1372 - 1383
(2012/04/04)
-
- One pot synthesis of [1,3]-oxazine and [1,3]-thiazine derivatives under thermal and microwave conditions
-
(Chemical Equation Presented) A simple and efficient synthesis of substituted benzo [1,3] oxazine and benzo [1,3] thiazine derivatives under conventional heating, as well as microwave irradiation is reported. The compounds were obtained by the reaction of electron rich phenols, formaldehyde, and aromatic amines in methanol. Reactions which take 12-16 hr under conventional heating were successfully completed within a few minutes under microwave irradiation (solventless) with moderate to excellent yields.
- Tumtin,Phucho,Nongpiur,Nongrum,Vishwakarma,Myrboh,Nongkhlaw
-
experimental part
p. 125 - 130
(2010/04/05)
-
- Qualitative analysis of the stability of the oxazine ring of various benzoxazine and pyridooxazine derivatives with proton nuclear magnetic resonance spectroscopy
-
A series of 3,4-dihydro-1,3-benzoxazine and 3,4-dihydro-1,3-pyridooxazine derivatives was synthesized, and the hydrolysis of the derivatives was studied with proton nuclear magnetic resonance spectroscopy. The oxazine derivatives underwent various degrees of hydrolysis when H2O was added to dimethyl sulfoxide solutions of the compounds. The rates and extents of decomposition of the oxazine ring systems depended on the electronic effects of substituents within the molecules. Examination of the proton nuclear magnetic resonance spectra that were generated during decomposition of the oxazines and trends in stability of the oxazine derivatives suggest the formation of an intermediate in the hydrolysis mechanism.
- Moloney,Craik,Iskander
-
p. 692 - 697
(2007/10/02)
-
- New Route for the Preparation of 2H-3-Aryl-3,4-dihydro-1,3-benzoxazines and 2H-3-Aryl-3,4-dihydro-4-methyl-1,3-benzoxazines
-
2-Hydroxybenzaldehyde (1) and 1-(2-hydroxyphenyl)ethanone (2) on reaction with different primary aromatic amines gave 2-(arylimino)methylphenols (3) and 2-phenols (4), respectively. 3 and 4 on reduction with sodium borohydride gave 2-(arylamino)methylphenols (5) and 2-phenols (6), which underwent cyclisation with formaldehyde to form 2H-3-aryl-3,4-dihydro-1,3-benzoxazines (7) and 2H-3-aryl-3,4-dihydro-4-methyl-1,3-benzoxazines (8), respectively.
- Joglekar, S. J.,Samant, S. D.
-
p. 110 - 111
(2007/10/02)
-