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l,5,7-Triazabicyclo[4.4.0]dec-5-ene (TBD),a bicyclic guanidine base,has been found to be an excellent catalyst for Michael and Michael-type reactions.A wide variety of Michael donors and acceptors can participate in these reaction...
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l,5,7-Triazabicyclo[4.4.0]dec-5-ene (TBD),a bicyclic guanidine base,has been found to be an excellent catalyst for Michael and Michael-type reactions.A wide variety of Michael donors and acceptors can participate in these reactions using 10-20 mol % of TDB.These reactions are mild,fast,easy to perform,produce excellent yields and can occur in several solvents without the need for strictly anhydrous conditions.
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Mycobacterium tuberculosis?is responsible for considerable human morbidity and mortality worldwide. Based on the presence or absence of?M. tuberculosis?specific deletion (TbD1),?M. tuberculosis?isolates are divided into ancestral ...
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Mycobacterium tuberculosis?is responsible for considerable human morbidity and mortality worldwide. Based on the presence or absence of?M. tuberculosis?specific deletion (TbD1),?M. tuberculosis?isolates are divided into ancestral and modern strains. The aim of this study was to differentiate ancestral and modern?M. tuberculosis?in northwest of Iran. 165?M. tuberculosis?strains were isolated from West and East Azarbaijan provinces of Iran. Ancient and modern?M. tuberculosisisolates were distinguished by primer specific polymerase chain reaction (PCR). This study showed that 49 (29.7%) of the isolates were modern?M. tuberculosis?and 116 (70.3%) were ancestral?M. tuberculosis. The prevalence of modern?M. tuberculosis?in West Azarbaijan was relatively higher than that of East Azarbaijan. Considering the increasing rate of modern?M. tuberculosis?in the studied region and in world, which has resulted in multi-drug resistance and low preventive effect of bacillus of calmette and guerin (BCG) vaccine, the fast diagnosis, prevention, treatment and more controlling programs of the infection, is important in this region.
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Although India accounts for the highest tuberculosis (TB) burden in the world, the diversity in prevalent Mycobacterium tuberculosis strains is very poorly documented. Tuberculosis specific deletion 1 (TbD1) is a marker that has b...
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Although India accounts for the highest tuberculosis (TB) burden in the world, the diversity in prevalent Mycobacterium tuberculosis strains is very poorly documented. Tuberculosis specific deletion 1 (TbD1) is a marker that has been used to differentiate ancient from modern strains. We report for the first time TbD1-based diversity in clinical M. tuberculosis isolates circulating in theNorth Indian states of Himachal Pradesh and Punjab. The present study documents a very high prevalence of modern strains in North India, which is in contrast to earlier studies that emphasised the predominance of ancestralstrains for the majority of TB cases in India.
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New synthesis of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) was developed from inexpensive and nontoxic chemicals. Guanidine, cyanamide, or their derivatives are heated with bis (3-aminopropyl)amine and a strong acid at 140-180 °C...
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New synthesis of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) was developed from inexpensive and nontoxic chemicals. Guanidine, cyanamide, or their derivatives are heated with bis (3-aminopropyl)amine and a strong acid at 140-180 °C for 7-9 h to form TBD in 95-97% yield.
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A series of 16 derivatives of pyrazole-triazole-chromene moieties (4a-p) were synthesized via one-pot cyclocondensation reaction of pyrazole-triazole aldehyde (1a-d), 1, 3 diketone (3a-d) and malononitrile (2a) in presence of PS-T...
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A series of 16 derivatives of pyrazole-triazole-chromene moieties (4a-p) were synthesized via one-pot cyclocondensation reaction of pyrazole-triazole aldehyde (1a-d), 1, 3 diketone (3a-d) and malononitrile (2a) in presence of PS-TBD as catalyst. The reusability of PS-TBD (polystyrene supported 7-methyl-1, 5, 7-triazabicyclo [4.4.0] dec-5-ene) catalyst makes this reaction quick and efficient. On the basis of various trials and its results, best performance and reusability of catalyst was observed at 5 mol% concentration. The reusability of catalyst founds up to 5 runs. A synthesized compound was characterized by <sup>1</sup>HNMR, <sup>13</sup>CNMR, FT-IR and C, H, N elemental analysis and confirms theoretical chemical reaction.
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The direct azidation of various heterocyclic β-ketoesters, lactones, and lactams is reported. By using tosy-lazide and an organic base such as L-proline or TBD, the direct α-insertion of azide into these substrates was achieved ...
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The direct azidation of various heterocyclic β-ketoesters, lactones, and lactams is reported. By using tosy-lazide and an organic base such as L-proline or TBD, the direct α-insertion of azide into these substrates was achieved in moderate to good yields, without competitive deacylating diazo transfer. This procedure represents an interesting alternative to the usual two-step approach of α-halogenation and subsequent displacement with azide ion.
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A new process for the preparation of non-isocyanate polyurethane (NIPU) flexible foams has been implemented. Biobased amino-telechelic NIPU oligomers were prepared by an organo-catalyzed transurethane poly-condensation reaction of...
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A new process for the preparation of non-isocyanate polyurethane (NIPU) flexible foams has been implemented. Biobased amino-telechelic NIPU oligomers were prepared by an organo-catalyzed transurethane poly-condensation reaction of fatty biscarbamates with fatty diols and diamines. The obtained oligomers were reacted with a biobased multi-epoxide molecule as crosslinking agent, in the presence of a poly(hydromethylsiloxane) or its copolymer as foaming agent and surfactant. The crosslinking and foaming reactions were monitored by rheometric, volumetric and FTIR studies. The foams can be obtained in < 30 min at 100 degrees C or in 14.5 h at room temperature. The prepared foams displayed cell diameters in the range of 210 to 430 mu m associated with densities in the range of 130 to 400 kg/m(3). They also exhibited thermal stabilities above 300 degrees C, as well as a soft character attested by negative Tg values ranging from -10 to-28 degrees C, and low values of the Young modulus varying from 1.0 x 10(4) Pa to 6.3 x 10(4) Pa. The recovery time, hysteresis loss and the firmness of these foams were found to be dependent on their chemical structures.
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AA-BB and AB-type Non-Isocyanate Polyurethanes (NIPUs) were synthesized through a cross metathesis polymerization between methyl carbamate and methyl carbonate groups within AA-BB and AB monomers. These monomers were prepared by r...
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AA-BB and AB-type Non-Isocyanate Polyurethanes (NIPUs) were synthesized through a cross metathesis polymerization between methyl carbamate and methyl carbonate groups within AA-BB and AB monomers. These monomers were prepared by reaction of diamines, diols or amino-alcohols with an excess of dimethylcarbonate (DMC), using 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as catalyst. Due to a slight chain extension, dimethyl dicarbonate monomers as well as AB-type monomers contained few carbonate groups, which were present within the final NIPUs. The polymerization was performed in bulk at 200 degrees C, using K2CO3 as catalyst. Except for AB-type monomers obtained from amino-alcohols with 3 and 4 methylene groups, the polymerization was successful leading selectively to the expected NIPUs. These materials exhibited good thermal properties with Tg ranging from- 35 to 10 degrees C, T-m ranging from 96 to 256 degrees C and degradation temperature above 200 degrees C. The polyurethane properties were generally intermediate comparing to those of polyurea and polycarbonate analogues prepared in the same conditions.
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Introduction: Teaching learning skills are developed through various skill lab procedures.In the Department of ENT and HNS, Temporal Bone Dissection (TBD) is one of the methods of teaching.The TBD workshop conducted in the Departm...
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Introduction: Teaching learning skills are developed through various skill lab procedures.In the Department of ENT and HNS, Temporal Bone Dissection (TBD) is one of the methods of teaching.The TBD workshop conducted in the Department caters to most of the postgraduate students in the country.This study was conducted in the Department of ENT and HNS to evaluate the participants’ satisfaction on TBD course conducted in the Department.Methods: The TBD participants who had undergone TBD course in the Department of ENT and HNS were asked to fill up the questionnaire regarding the satisfaction of the TBD course and suggestions for the improvement of the course.The participants provided the response of the questionnaire in the email or in hand filling of the forms.Results: Total of 42 students responded to the questionnaire regarding the TBD course.88% of the students graded it as good, 11% replied as satisfactory and 1% of them graded it as needs improvement.Maximum number of students commented on the inadequate time for dissection.Few participants replied the need of live demonstration in the course.9.5% of the participants who had come for the course more than once commented on the great help done by the course in performing live otology surgery.Conclusions: Maximum participants were satisfied about the TBD workshop which helped them to know the intricate temporal bone anatomy.
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An efficient approach to N, N'-unsymmetrically substituted ureas 9 has been developed through the ammonolysis process of N-Boc protected anilines 7 with amines prompted by 1,5,7-triazabicyclo[4.4.0] dec-5-ene (TBD). Moreover, a co...
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An efficient approach to N, N'-unsymmetrically substituted ureas 9 has been developed through the ammonolysis process of N-Boc protected anilines 7 with amines prompted by 1,5,7-triazabicyclo[4.4.0] dec-5-ene (TBD). Moreover, a convenient protocol for the synthesis of the symmetric N, N'-substituted ureas 12 by one-pot diammonolysis process of Boc(2)O with amines catalyzed by DABCO has also been achieved. With broad substrate scope and mild conditions, these two methods demonstrate practical preparation of both unsymmetrical and symmetrical ureas. (C) 2017 Published by Elsevier Ltd.
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