An expedient and new synthesis of pyrrolo[1,2-b]pyridazine derivatives

• Rajeshwar Reddy Sagyam,
• Ravinder Buchikonda,
• Jaya Prakash Pitta,
• Himabindu Vurimidi,
• Pratap Reddy Padi and
• Mahesh Reddy Ghanta

Beilstein J. Org. Chem. 2009, 5, No. 66, doi:10.3762/bjoc.5.66

• cycloaddition of dimethyl acetylenedicarboxylate to the Reissert compound of pyridazine [20], the 1,3-dipolar cycloaddition of pyridazinium dichloromethylide generated by the carbene method [21], and the cycloaddition of alkylidene cyclopropane derivatives to pyridazine in the presence of Pd(PPh3)4 [22

The tert- amino effect in heterocyclic chemistry: Synthesis of new fused pyrazolinoquinolizine and 1,4-oxazinopyrazoline derivatives

• Dipak Prajapati and
• Kalyan Jyoti Borah

Beilstein J. Org. Chem. 2007, 3, No. 43, doi:10.1186/1860-5397-3-43

• undergoing a 1,5-(4 → 5) hydride shift prior to cyclization to yield a 6-membered ring product 6 (Scheme 2). This is in contrast to an earlier report by Sandhu et al to obtain pyrrolo [2,3-d]pyrimidines from 6-tert-amino-substituted uracils and dimethyl acetylenedicarboxylate.[32] However, further work is in

Trapping evidence for the thermal cyclization of di-(o-acetylphenyl)acetylene to 3,3'-dimethyl- 1,1'-biisobenzofuran

• Charles P. Casey,
• Neil A. Strotman and
• Ilia A. Guzei

Beilstein J. Org. Chem. 2005, 1, No. 18, doi:10.1186/1860-5397-1-18

• Charles P. Casey Neil A. Strotman Ilia A. Guzei University of Wisconsin-Madison, Madison, WI 53706 10.1186/1860-5397-1-18 Abstract The reaction of di-(o-acetylphenyl)acetylene (1) with excess dimethyl acetylenedicarboxylate (DMAD) produced bis-DMAD adducts meso-3 and rac-3. This transformation is

• decomposition process. Here we report evidence for a bicyclization reaction of 1 leading to the first biisobenzofuran, and its trapping by reaction with dimethyl acetylenedicarboxylate (DMAD). An X-ray crystal structure of the resulting bis Diels-Alder adduct of this highly unstable isobenzofuran is reported