50727-07-6Relevant academic research and scientific papers
N -Chlorinative Ring Contraction of 1,4-Dimethoxyphthalazines via a Bicyclization/Ring-Opening Mechanism
Im, Jeong Kyun,Jeong, Ilju,Yang, Byeongdo,Moon, Hyeon,Choi, Jun-Ho,Chung, Won-Jin
, p. 1760 - 1770 (2020/12/30)
An unprecedented N -chlorinative ring contraction of 1,2-diazines was discovered and investigated with an electrophilic chlorinating reagent, trichloroisocyanuric acid (TCICA). Through optimization and mechanistic analysis, the assisting role of n -Bu 4NCl as an exogenous nucleophile was identified, and the optimized reaction conditions were applied to a range of 1,4-dimethoxyphthalazine derivatives. Also, an improvement of overall efficiency was demonstrated by the use of a labile O -silyl group. A bicyclization/ring-opening mechanism, inspired by the Favorskii rearrangement, was proposed and supported by the DFT calculations. Furthermore, the efforts on scope expansion as well as the evaluation of other electrophilic promoters revealed that the newly developed ring contraction reactivity is a unique characteristic of 1,4-dimethoxyphthalazine scaffold and TCICA.
Direct Cyclopropanation of α-Cyano β-Aryl Alkanes by Light-Mediated Single Electron Transfer Between Donor–Acceptor Pairs
Li, Jing,Lear, Martin J.,Hayashi, Yujiro
supporting information, p. 5901 - 5905 (2021/03/09)
Cyclopropanes are traditionally prepared by the formal [2+1] addition of carbene or radical based C1 units to alkenes. In contrast, the one-pot intermolecular cyclopropanation of alkanes by redox active C1 units has remained unrealised. Herein, we achieve
Transition metal-free 1,3-dimethylimidazolium hydrogen carbonate catalyzed hydration of organonitriles to amides
Verma, Praveen Kumar,Sharma, Upendra,Bala, Manju,Kumar, Neeraj,Singh, Bikram
, p. 895 - 899 (2013/04/23)
An efficient hydration of organonitriles to the corresponding amides was accomplished using 1,3-dimethylimidazolium hydrogen carbonate as an organocatalyst. The developed catalytic method was also applicable for the synthesis of metal phthalocyanines.
Transition metal-free sodium borohydride promoted controlled hydration of nitriles to amides
Verma, Praveen Kumar,Kumar, Neeraj,Sharma, Upendra,Bala, Manju,Kumar, Vishal,Singh, Bikram
, p. 2867 - 2875 (2013/09/02)
A transition metal-free process, promoted by sodium borohydride, has been developed for convenient and selective hydration of nitriles to corresponding amides. The present process converts the aromatic, aliphatic, and heteroaromatic nitriles with wide functional group tolerance. The regioselective hydration of one nitrile moiety in the presence of an other nitrile group makes high impact in the present protocol.
Inhibitors of dipeptidyl peptidase 8 and dipeptidyl peptidase 9. Part 2: Isoindoline containing inhibitors
Van Goethem, Sebastiaan,Van der Veken, Pieter,Dubois, Veronique,Soroka, Anna,Lambeir, Anne-Marie,Chen, Xin,Haemers, Achiel,Scharpe, Simon,De Meester, Ingrid,Augustyns, Koen
scheme or table, p. 4159 - 4162 (2009/05/07)
To obtain selective and potent inhibitors of dipeptidyl peptidases 8 and 9, we synthesized a series of substituted isoindolines as modified analogs of allo-Ile-isoindoline, the reference DPP8/9 inhibitor. The influence of phenyl substituents and different P2 residues on the inhibitors' affinity toward other DPPs and more specifically, their potential to discriminate between DPP8 and DPP9 will be discussed. Within this series compound 8j was shown to be a potent and selective inhibitor of DPP8/9 with low activity toward DPP II.
Regiochemistry of the photostimulated reaction of the phthalimide anion with 1-iodoadamantane and tert-butylmercury chloride by the SRN1 mechanism
Maquieira, Manuel Bajo,Penenory, Alicia B.,Rossi, Roberto A.
, p. 1012 - 1015 (2007/10/03)
The photostimulated reaction of the phthalimide anion (1) with 1-iodoadamantane (2) gave 3-(1-adamantyl) phthalimide (3) (12%) and 4-(1-adamantyl) phthalimide (4) (45%), together with the reduction product adamantane (AdH) (21%). The lack of reaction in the dark and inhibition of the photoinduced reaction by p-dinitrobenzene, 1,4-cyclohexadiene, and di-tert-butylnitroxide indicated that 1 reacts with 2 by an SRN1 mechanism. Formation of products 3 and 4 occurs with distonic radical anions as intermediates. The photoinduced reaction of anion 1 with tert-butylmercury chloride (10) affords 4-tert-butylphthalimide (11) as a unique product. By competition experiments toward 1, 1-iodoadamantane was found to be ca. 10 times more reactive than tert-butylmercury chloride.
Homolytic base-promoted aromatic alkylations by alkyl halides
Wang, Chen,Russell, Glen A.,Trahanovsky, Walter S.
, p. 9956 - 9959 (2007/10/03)
Electron-transfer chain reactions leading to regioselective alkylations of benzenes bearing electron-withdrawing substituents can be observed with alkyl halides in the presence of the radical initiator (Bu3Sn)2 and the proton acceptor 1,4-diazabicyclo[2.2.2]octane (DABCO). Yields vary from low to high depending on the benzene derivatives. The role of DABCO is to abstract a proton from the substituted cyclohexadienyl adduct radical to form a radical anion which then transfers an electron to RX and is converted to the alkylated product itself. The rate of this electron-transfer step is probably not fast enough to sustain a good radical chain reaction so that further generation of R· from excess (Bu3Sn)2 and RX is necessary.
Homolytic base-promoted aromatic alkylations by alkylmercury halides
Russell, Glen A.,Chen, Ping,Kim, Byeong Hyo,Rajaratnam, Ragine
, p. 8795 - 8801 (2007/10/03)
Electron transfer chain reactions leading to substitution in electronegatively substituted benzene derivatives can be observed with alkylmercury halides in the presence of proton accepters such as DABCO. Promotion by base involves the abstraction of a proton from the substituted cyclohexadienyl adduct radical to form a radical anion which readily transfers an electron to RHgX with the regeneration of R.. Aromatic substitutions involving t-Bu. are highly regioselective and yield products of only para attack for PhCHO, PhCOCH3, PhCOCMe3, PhCOPh, PhCN, phthalimides, or 1,2-dicyanobenzene. The ortho/para substitution products are observed for isophthaldehyde or 1,3-dicyanobenzene, while 1,4-dicyanobenzene yields the ortho substitution product. At 25-35°C substitution by t-Bu. ortho to an ester group is not observed and m- or p-cyanobenzoate esters yield only products of substitution ortho to the cyano group. With the isopropyl radical substitution ortho to the ester function is observed with diethyl isophthalate. Intramolecular radical cyclizations of the radical adducts of 1-aryl-4-penten-1-ones leading to α-tetralones is also promoted by the presence of DABCO. When the aryl group contains a para ester function, spirocyclizatien occurs leading to a rearrangement acyl radical which can be oxidized by t-BuHgCl to the acyl cation and the carboxylic acid.
Synthesis of Tetrakis(4-tert-butylbenzo)porphin and its Metal Complexes
Mamardashvili, N. Zh.,Semeikin, A. S.,Golubchikov, O. A.
, p. 818 - 821 (2007/10/02)
The condensation of 4-tert-butylphthalimide with sodium and zinc acetates leads to the zinc complex of tetrakis(4-tert-butylbenzo)porphin, which forms the free ligand under the influence of boiling trifluoroacetic acid.A series of metalloporphyrins were obtained from tetrakis(4-tert-butylbenzo)porphin and metal acetates.
Kinetic and equilibrium in the ammonolysis of substituted phthalimides
McClelland, Robert A.,Seaman, N. Esther,Duff, James M.,Branston, R. E.
, p. 121 - 128 (2007/10/02)
Kinetic studies are reported for the base hydrolysis to phthalamic acid anions (H) and ammonolysis to phthalamides (A) for seven phthalimides (P): 1, unsubstituted; 2, 4-NO2; 3, 4-Cl; 4, 4-tBu; 5, 3-NO2; 6, 3-Me; 7, 3-Me3Si.The hydrolysis kinetics require two mechanisms, one which is first order in neutral imide and first order in hydroxide ion, and a second, which is important only in quite concentrated NaOH, which is first order in neutral phthalimide and second order in hydroxide ion.Ammonolysis kinetics for 1-5 revealed the rate law: Rate = kN ->.A mechanism is proposed with rate-determining breakdown of the anionic form of the tetrahedral intermediate derived by addition of NH3 to the phthalimide.The ammonolysis is reversible.The phthalamide hydrolyzes to the phthalamic acid via cyclization to an intermediate phthalimide, which is detected in concentrated base where its formation from phthalamide is more rapid than its subsequent hydrolysis.Rate constants for the cyclization follow the rate law: Rate = kcyc ->.This reaction is the microscopic reverse of the ammonolysis, and the ratio kN/kcyc provides the equilibrium constant Keq for the reaction P + NH3 = A.Values for 1-5 lie in the range 2 x 102 - 4 x 103.With 3-methylphthalimide, kinetics in aqueous ammonia do not obey a first-order relationship, but they could be analyzed by a scheme whereby the phthalimide is converted reversibly to the phthalamide and simultaneously undergoes an irreversible hydrolysis.The value of Keq in the system is 1.8.With 3-trimethylsilylphthalimide the value of Keq is further reduced to 0.01.The ammonolysis reaction does occur more quickly than hydrolysis but the equilibrium is so unfavorable that even in concentrated ammonia only a small amount of the phthalamide is ever formed.
