Catalyst-free conditions

Masjedizadeh and coworkers have recently described similar microwave-promoted hydrogen-deuterium exchange reactions in a series of heterocydes using mixtures of deuterium oxide and deuteriomethanol (Scheme 6.173 b) [328], The rapid exchange method was applied to the deuteration of the anti-tumor antibiotic bleomycin A under catalyst-free conditions [328],... 

Where R = H or Me and Rj = Aiyl and substituted aryl groups Scheme 6.24 Formation of hydrazones under solvent-free and catalyst-free conditions. 

A variety of other environmentally friendly strategies for the synthesis of quinolines were also reported. Goswami et al. developed a one-pot approach for the synthesis of quinolines from aromatic amines and P-aryl vinyl ketones under solvent and catalyst free conditions <07JHC1191>. In another solvent free one-pot method, Nagarajan et al. synthesized 3-quinolylcarbazoles from P-nitrovinylcarbazole and 2-amino acetophenone in moderate yields <07TL2489>. 

In our previous studies, water-soluble products are also considered as intermediates for the oil/char production under catalyst free conditions ... 

Minowa, T., Zhen, F., Ogi, T. and Varhegyi, G. (1998) Decomposition of cellulose and glucose in hot-compressed water under catalyst-free condition. J. Chem. Eng. Jpn.,3, 131-134. 

Mirza-Aghayan, M., Ghassemzadeh, M., Hoseini, M., Bolourtchian, M. Microwave-assisted synthesis of the tetradentate Schiff-bases under solvent-free and catalyst-free condition. Synth. Commun. 2003, 33, 521-525. 

Ranu, B. C., Dey, S. S., Hajra, A. Highly efficient acylation of alcohols, amines and thiols under solvent-free and catalyst-free conditions. Green Chem. 2003, 5, 44 6. 

Addition of isocyanides to polarized multiple bonds generally occurs under catalyst-free conditions and indeed most of the isocyanide-based MCRs (IMCRs) described above took place readily in the absence of an external reagent, which... 

The rate of this reaction is so slow under catalyst-free conditions in the gas phase that it can be totally neglected as a source of atmospheric S03. 

Scheme 8.29. Formation of hydrazones under solvent-free and catalyst-free conditions.

The first example of a reaction between two solids, under solvent-free and catalyst-free conditions, was demonstrated [41] when the reaction of neat 5- or 8-oxobenzo-... 

A novel green process for intermolecular hydroarylation of in situ generated o-QMs with electron-rich arenes in aqueous medium under catalyst-free conditions at room temperature has been developed. The reaction is efficient and highly regioselective (Scheme 7.62). 

M hamed MO, Alduaij OK. An efficient one-pot synthesis of new 2-thioxo and 2-oxo-pyrimidine-5-carbonitriles in ball-milling under solvent-free and catalyst-free conditions. Phosph Sulfur Silicon 2014 189 235-41. 

Recently, atom-economical cyanation process under catalyst-free conditions has been developed using acetone cyanohydrin [84] in water, as an example of mild and alternative cyanide source (Scheme 10.30) [85]. 

For other example, see J. Wang, Y. Masni, M. Onaka, Eur. J. Org. Chem. 2010, 1763-1771. Synthesis of a-amino nitriles from carbonyl componnds, amines, and trimethylsUyl cyanide comparison between catalyst-free conditions and the presence of tin ion-exchanged montmoriUonite. 

For synthesis of a-aminophosphonates under catalyst and ultrasonic irradiation, see M. Xia, Y.-D. Lu, Ultrason. Sonochem. 2007, 14, 235-240. Ultrasound-assisted one-pot approach to a-amino phosphonates under solvent-free and catalyst-free conditions. 

Uncatalyzed one-pot diastereoselective synthesis of a-amino phosphonates under solvent-free conditions, (b) G. D. Tibhe, V. Labastida-Galvan, M. Ordonez, Rapid Common. Mass Spectrom. 2011, 25, 951-959. Study of the fragmentation pathway of a-aminophosphonates by chemical ionization and fast atom bombardment mass spectrometry, (c) J. L. Viveros-Ceballos, C. Cativiela, M. Orddnez, Tetrahedron Asymmetry 2011, 22, 1479-1484. One-pot three-component highly diastereoselective synthesis of isoindohn-l-one-3-phosphonates under solvent and catalyst free-conditions. (d) G. D. Tihhe,... 

M. A. Reyes-Gonzdlez, C. Cativiela, M. Orddnez, J. Mex. Chem. Soc. 2012, 56, 183-187. Microwave-assisted high diastereoselective synthesis of a-aminophosphonates under solvent and catalyst free-conditions. 

As mentioned before for the synthesis of pyridones, 5-unsubstimted pyrimidinones 186 can be accessed by utilizing Meldrum s acid 112 as the CH-acidic component (Scheme 13.44) [77], In refluxing ethanol, the desired product could be obtained under catalyst-free conditions in moderate to good yields (51-83%). In DMF at high temperatures with the use of an amino-functionaUzed highly porous MCM-41 catalyst, the yields could be increased, as reported by Mirza-Aghayan et al. [78],... 

Tu S, Shao Q, Zhou D, Cao L, Shi F, Li C (2007) Microwave-assisted efficient synthesis of benzo[4,5]imidazo[l,2-a]pyrimidine derivatives in water under catalyst-free conditions. J Heterocycl Chem 44 1401-1406... 

Zhao LQ, Zhou B, Li YQ (2011) An efficient one-pot three-component reaction for synthesis of spirooxindole derivatives in water media under catalyst-free condition. Heteroat Chem... 

A one-pot four-component reaction of aldehyde, phthalic anhydride, hydrazini-um hydroxide, and dimedone nnder nltrasonic irradiation in IL [BMImJBr has been described, which generated various 2 H-indazolo[2,l-b]phthalazinetriones in good yields under neutral and catalyst-free conditions [114] (Scheme 7.12). 

Murthy SN, Madhav B, NageswarYVD (2010) Revisiting the Hinsberg reaction facile and expeditious synthesis of 3-substituted quinoxalin-2(lH)-ones under catalyst-free conditions in water. Helv Chim Acta 93 1216-1220... 

A CPN-fused dibenzocyclooctyne 70 was prepared by Boons (Scheme 6.11). It undergoes fast strain-promoted cycloadditions with azides under catalyst-free conditions to yield a triazole 71, displaying more than 1000-fold brighter fluorescence than 70 [40]. 

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