144522-58-7Relevant articles and documents
Aziridination of alkenes with 3-acetoxyaminoquinazolinones in the presence of hexamethyldisilazane
Atkinson, Robert S.,Barker, Emma,Ulukanli, Sabri
, p. 583 - 589 (2007/10/03)
Yields of aziridines from reaction of some alkenes, including α,β-unsaturated esters, with 3-acetoxyamino-2-isopropylquinazolinone 6 (Q3NHOAc) are greatly increased in the presence of hexamethyldisilazane (HMDS). A mono-aziridination product of naphthalene is obtained only in the presence of HMDS. It is concluded that the enhanced yields in these aziridinations are the result of scavenging of acetic acid by HMDS, thus prolonging the lifetime of the aziridinating agent Q3NHOAc.
N-Acetyl-N-acyl-3-aminoquinazolinones as chemoselective acetylating agents
Atkinson, Robert S.,Barker, Emma,Sutcliffe, Michael J.
, p. 1051 - 1052 (2007/10/03)
The title compounds, e.g. 3, are highly selective acetylating agents for primary amines in the presence of secondary amines and, in particular, for the less sterically hindered of two different secondary amines.
Lithiation of 3-(acylamino)-2-unsubstituted-, 3-(acylamino)-2-ethyl-, and 3-(acylamino)-2-propyl-4(3H)-quinazolinones: Convenient syntheses of more complex quinazolinones
Smith,El-Hiti,Abdel-Megeed,Abdo
, p. 647 - 655 (2007/10/03)
3-(Pivaloylamino)- and 3-(acetylamino)-4(3H)-quinazolinones react with alkyllithium reagents to give 1,2-addition products in very good yields. Lithiation takes place with LDA and is regioselective at position 2. The lithium reagents thus obtained react with a variety of electrophiles to give the corresponding substituted derivatives in very good yields. Reactions of the lithium reagents with iodine give oxidatively dimerized cyclic structures. 3-(Pivaloylamino)- and 3-(acetylamino)-2-ethyl-4(3H)-quinazolinones and 3-(pivaloylamino)- and 3-(acetylamino)-2-propyl-4(3H)-quinazolinones are lithiated at the benzylic position with LDA. The lithium reagents so produced also react with a variety of electrophiles to give the corresponding 2-substituted-4(3H)-quinazolinone derivatives in very good yields. However, lithiation of 3-(acylamino)-2-(1-methylethyl)-4(3H)-quinazolinones was unsuccessful, as were lithiations of compounds having a diacetylamino group at position 3. The amide groups have been cleaved in good yield under basic or acidic conditions from some of the products to provide access to the free amino compounds.
The N-N bond as a chiral axis: 3-diacylaminoquinazolinones as chiral acylating agents
Atkinson, Robert S.,Barker, Emma,Edwards, Paul J.,Thomson, Gordon A.
, p. 1047 - 1055 (2007/10/03)
3-Diacylaminoquinazolinones 10 and 15 have high enough barriers to rotation around their N-N bonds to allow separation of each into diastereoisomers. Interconversion of diastereoisomers 10a and 10b occurs on heating in boiling toluene and thermodynamic parameters for this process have been measured. The barriers to rotation around the N-N bonds in analogous monoacylaminoquinazolinones are not sufficient to permit isolation of stereoisomers at room temperature unless the exocyclic nitrogen is additionally substituted e.g. by an alkyl group as in 28. X-Ray crystal structure determinations carried out on 10a, 10b, 15a and 28b confirm the presence of chiral axes. Reaction of both diastereoisomers 15a and 15b with 1-phenylethylamine takes place with exclusive reaction at the 1-acetoxypropionyl carbonyl group and with partial kinetic resolution: the preferred sense of enantioselectivity obtained is dominated by the N-N axis.
Reaction of 3-(Acetoxyamino)quinazolin-4(3H)-ones with Enolic β-Diketones: the N-N Bond as a Chiral Axis in N-(3,4-dihydro-4-oxoquinazolin-3-yl)-N-acyl-α-aminoketones; Reductive and Base-catalysed Cleavage of the N-N Bond in N-Acetyl-N-(3,4-dihydro-4-oxoquinazolin-3-yl)-α-amino Aci...
Atkinson, Robert S.,Edwards, Paul J.,Thomson, Gordon A.
, p. 3209 - 3216 (2007/10/02)
Following the method of Foucaud and coworkers, reaction of pentane-2,4-dione with 3-(acetoxyamino)quinazolin-4-one 8 gave the keto amide 9 (15percent). 3-Methylpentane-2,4-dione reacts with compound 8 to give a relatively stable enol 11 (66percent) which can be isolated in a crystalline form.Rotation around the N-N bonds in both compounds 9 and 11 is believed to be slow on the real time-scale and hence the N-N bonds can be considered as a chiral axes.As a result, protonation of the enol double bond in compound 11 and the creation of an additional chiral centre, gives rise to the separable keto amides 14 and 15; this protonation can be accomplished completely diastereoselectively.Lead tetraacetate acetoxylation of compound 11 to give compound 11 to give compound 19 is also completely diastereoselective.Brief heating of the enol effects the elimination of the quinazolinone and the formation of the N-acetylimine 16 via an 8-membered transition state.Base-catalysed elimination of the quinazolinone ring from compound 22 is surprisingly easy: reductive cleavage of this N-N bond in compound 22 is facile by comparison with the 3-(alkylamino)quinazolin-4-ones.
Asymmetric Induction Mediated by an N-N Chiral Axis
Atkinson, Robert S.,Edwards, Paul J.,Thomson, Gordon A.
, p. 1256 - 1257 (2007/10/02)
Reaction of 3-methylpentane-2,4-dione 11 with N-acetoxyaminoquinazolinone 6 gives an isolable enol 12, which is chiral by virtue of the high barrier to rotation around its N-N bond; protonation of the double bond occurs in glacial acetic acid to give a single diastereoisomer of keto-amide 13.
