Pyrido pyrimidines, chemistry

Oxazolo[5,4-d]pyrimidines, synthesis and reactivity of 86AKZ211. Perimidines (naphtho[l,8-general review 81 UK 1559. Pyrido[l,2-fl]pyrimidines, chemistry of 83AHC(33)241. 

Chemistry of benzologs of pyrido[l,2-<2]pyrimidines 99AHC(73)177. Synthesis, chemistry, and biological properties of thienopyrimidines ... 

The synthesis of pyrido[2,3-d]pyrimidines has attracted considerable interest in heterocyclic chemistry. This ring system constitutes a deaza-analogue of the pyrazino[2,3-d]pyrimidine heterocychc core of fohc acid, analogues which can exhibit a wide range of biological properties as folate antagonists. Thus, the synthesis of this motif by MCR imder microwave-assisted conditions has the potential to rapidly introduce diversity into a biologically relevant scaffold. 

Dr. Istvan Hermecz (Chinoin, Budapest, Hungary) covers the chemistry of pyrido[l,2-6][l,2]oxazines, -thiazines, and -pyridazines and their benzo-logs, compound classes that have not previously been reviewed but which in recent years have shown increasing significance with regard to their biological and other properties. This forms the first installment of a set of three chapters the subsequent installments in later volumes of our series will deal with (i) [l,2-c]-fused 1,3-oxazines, 1,2-thiazines, and pyrimidines (ii) [2,l-6]-fused analogs and (iii) fused 1,4-oxazines and 1,4-thiazines. 

Chemistry of Benzologs of Pyrido 1,2-a ] pyrimidines Part V of Series on Pyrido-oxazines, -diazines, and -thiazines... 

The chemistry of l,2,4-triazolo[4,3-a]pyrimidines is covered in the first installment of a general treatment of 1,2,4-triazolopyrimidines (isostears of purines) by Professor M. A. E. Shaban and Dr. A. E. A. Morgaan (Alexandria University, Egypt). The final installment of Dr. I. Hermecz s (CHINOIN Ltd., Hungary) five-part-series on pyrido-oxazines, -diazines, and -thiazines comprises Chapter 4 of the present volume and covers ben-zologs of pyrido[l,2,-a]pyrimidines. Parts I through IV appeared in Volumes 69-72 of our series. 

The next chapter continues the series by Dr. I. Hermecz (Budapest, Hungary) on the chemistry of pyridooxazines and -thiazines. This chapter, Part IV of the series, deals with the chemistry of pyrido[2,l-6][l,3] oxazines and [l,3]thiazines together with their benzologs. The first three parts of the series comprised Part I in Volume 69 on pyrido[l,2-b]-l,2-oxazines, -1,2-thiazines, and -pyridazines and their benzologs Part II in Volume 70 on pyrido[l,2-c]-l,3-oxazines, -1,3-thiazines, and -pyrimidines and their benzologs and Part III in Volume 71 on pyrido[2,l-c]-l,4-oxazines, -1,4-thiazines, and -pyrazines and their benzologs. 

The chemistry of the pyrido[l,2-a]pyrimidines has previously been reviewed by Mosby1, who found 43 references to this ring system while covering the literature up to 1957. Many of the early articles have been found to contain erroneous statements, and therefore these publications have also been included in the present work. 

Sec. II.A] CHEMISTRY OF PYRIDO[l,2-ti]PYRIMIDINES II. Preparation of Pyrido[l,2-a]pyrimidines... 

Sec. II.C] CHEMISTRY OF PYRIDO[1.2-u]PYRIMIDINES 1. From fi-O.xo Esters and Their Congeners... 

---