- Metal-Free Transamidation of Secondary Amides by N-C Cleavage
-
Transamidation reactions represent a fundamental chemical process involving conversion of one amide functional group into another. Herein, we report a facile, highly chemoselective method for transamidation of N-tert-butoxycarbonylation (N-Boc) activated secondary amides that proceeds under exceedingly mild conditions in the absence of any additives. Because this reaction is performed in the absence of metals, oxidants, or reductants, the reaction tolerates a large number of useful functionalities. The reaction is compatible with diverse amides and nucleophilic amines, affording the transamidation products in excellent yields through direct nucleophilic addition to the amide bond. The utility of this methodology is highlighted in the synthesis of Tigan, a commercial antiemetic, directly from the amide bond. We expect that this new metal-free transamidation will have broad implications for the development of new transformations involving direct nucleophilic addition to the amide bond as a key step.
- Rahman, Md. Mahbubur,Li, Guangchen,Szostak, Michal
-
p. 12091 - 12100
(2019/10/11)
-
- Generation and trapping of ketenes in flow
-
Ketenes were generated by the thermolysis of alkoxyalkynes under flow conditions, and then trapped with amines and alcohols to cleanly give amides and esters. For a 10 min reaction time, temperatures of 180, 160, and 140 °C were required for >95% conversion of EtO, iPrO, and tBuO alkoxyalkynes, respectively. Variation of the temperature and flow rate with inline monitoring of the output by IR spectroscopy allowed the kinetic parameters for the conversion of 1-ethoxy-1-octyne to be easily estimated (Ea = 105.4 kJ/mol). Trapping of the in-situ-generated ketenes by alcohols to give esters required the addition of a tertiary amine catalyst to prevent competitive [2+2] addition of the ketene to the alkoxyalkyne precursor.
- Henry, Cyril,Bolien, David,Ibanescu, Bogdan,Bloodworth, Sally,Harrowven, David C.,Zhang, Xunli,Craven, Andy,Sneddon, Helen F.,Whitby, Richard J.
-
p. 1491 - 1499
(2015/03/04)
-
- Nickel-catalyzed cross-coupling of unactivated alkyl halides and tosylate carrying a functional group with alkyl and phenyl Grignard reagents
-
By the use of catalytic amounts of a nickel salt and a 1,3-butadiene, primary and secondary alkyl Grignard reagents undergo cross-coupling with alkyl bromides, iodide, and tosylate carrying a functional group such as amide, ester, and ketone at 0 °C in THF. The present procedure provides a simple, convenient, and practical method for construction of carbon chains in the presence of various functional groups. PhMgBr also gave the corresponding coupling product in a moderate yield.
- Singh, Surya Prakash,Terao, Jun,Kambe, Nobuaki
-
scheme or table
p. 5644 - 5646
(2011/02/25)
-
- Leishmanicidal potential of N-substituted morpholine derivatives: Synthesis and structure-activity relationships
-
A series of N-substituted morpholines 2-20 was synthesised by reacting various acid chlorides and alkyl halides with morpholine (1). All of the synthesised compounds 2-20 were screened for their leishmanicidal effects using amphotericin B (IC50 = 0.24 μg L-1) and pentamidine (IC50 = 2.56 μg mL-1) as standards and a structure-activity relationship (SAR) study was established. The compounds 2 (IC50 = 48 μg mL-1), 3 (IC50 = 30.0 μg mL-1), 10 (IC50 = 41.0 μg mL-1), 15 (IC50 = 33.0 μg mL-1), 16 (IC50 = 35.0 μg mL-1) and 20 (IC50 = 47.0 μg mL-1) showed weak leishmanicidal activities.
- Khan, Khalid Mohammed,Khan, Muhammad Zarrar,Taha, Muhammad,Maharvi, Ghulam Murtaza,Saify, Zafar Saeed,Parveen, Shahnaz,Choudhary, Muhammad Iqbal
-
experimental part
p. 479 - 484
(2010/06/21)
-
- Addition of organocerium reagents to morpholine amides: synthesis of important pheromone components of Achaea janata.
-
Readily preparable morpholine amides hitch in good yields with organocerium reagents to produce ketones. Even in the presence of substrates and reagents with high steric hindrance, the organometallic compounds prepared from dry cerium(III) chloride and organomagnesium or organolithium compounds at -78 degrees C add cleanly to morpholine amides. The low cost of starting materials makes this new scheme of synthesis very interesting for the preparation of biologically important pheromones.
- Badioli, Michele,Ballini, Roberto,Bartolacci, Massimo,Bosica, Giovanna,Torregiani, Elisabetta,Marcantoni, Enrico
-
p. 8938 - 8942
(2007/10/03)
-
- Transdermal compositions of 1-oxohydrocarbyl-substituted azacyclohexanes
-
This invention provides compositions for enhancing penetration of physiologically active agents through the skin or mucosal membranes and for retaining these agents in body tissues, said composition comprising effective amounts of a physiologically-active agent and a compound represented by the general formula STR1 wherein X may represent sulfur, oxygen or nitrogen; a and b may be 0 or 1, c may be 0, 1 or 2, except that when X is oxygen, a, b and c are 0, when X is nitrogen c is 0 and only one of a or b is 1, and when X is sulfur a and b are 0; A is a branched or a straight chain, divalent aliphatic radical having from 0 to 2 double bonds; R' is selected from the group consisting of H, a lower alkyl group having from 1 to 4 carbon atoms, phenyl, lower alkyl or halogen substituted phenyl, acetamido, halogen, piperidinyl, lower alkyl or halogen substituted piperidinyl, carbalkoxy, carboxamide, and alkanoyl; and R is hydrogen or a lower alkyl group having from 1 to 4 carbon atoms, STR2 wherein R" is H or halogen, and salts, e.g. acid or quaternary derivatives, thereof. These compositions are useful in topical or transdermal applications of the physiologically-active agent.
- -
-
-