The Front Cover illustrates how the pyridine ring of antihistamine loratadine can be selectively functionalised at ortho-, meta-, or para-position (each them activated by a thunder). Indeed, selective functionalisation this N-heterocycle is often problematic, thus lighthouse guides chemists through late-stage functionalisations pyridine-containing biomolecules. More information found in Review ...

M . R ö s s l e r [1] , W . S c h w a r z u n d A . S c h m i d t Institut für Anorganische Chemie der Universität Stuttgart Z . Naturforsch. 34b , 398-405 (1978); eingegangen am 9. Oktober/5. Dezember 1978 Oxal ic Ac id Methylester-N-methylamides, A n t i m o n y ( V ) Chloride Oxalic acid dimethylester and the oxalic acid methylester-N-methylamides 2 and 4, resp., react with ant imony(V) chlo...

we denote by $ls[n](t,k,v)$ a large set of $t$-$(v,k,lambda)$ designs of size $n$, which is a partition of all  $k$-subsets ofa $v$-set into $n$ disjoint  $t$-$(v,k,lambda)$ designs and$n={v-t choose k-t}/lambda$.   we use the notation$n(t,v,k,lambda)$ as the maximum possible number of mutuallydisjoint cyclic $t$-$(v,k,lambda)$designs. in this paper we givesome new bounds for $n(2,29,4,3)$ and ...

The mol-ecule of the title compound, C(8)H(6)N(2)OS(2), has a V shape with two five-membered rings attached to a methyl-ene C atom. All non-H atoms are approximately coplanar (r.m.s. deviation = 0.096 Å). In the crystal, mol-ecules are linked by N-H⋯O hydrogen bonds into layers. The thio-phene ring is disordered over two positions; the major orientation has an occupancy of 0.683 (3). is there a...

A graph G = (V,E) is called a hyper-ring with N nodes (N-HR for short) if V = {O,...,N 1) and E = {{u,u}1u U modulo N is a power of 2). We study constructions and spanners of HRs, and embeddings into HRs. The stretch factors of three types of spanners given in this paper are at most [log, q, 2k1 for any 15 k 5 rlog,N], and 2k1 for any 0 5 k 5 [log, N] 1, respectively. The numbers of edges of th...

let $g=(v,e)$ be a simple graph. a set $ssubseteq v$ isindependent set of $g$,  if no two vertices of $s$ are adjacent.the  independence number $alpha(g)$ is the size of a maximumindependent set in the graph. in this paper we study and characterize the independent sets ofthe zero-divisor graph $gamma(r)$ and ideal-based zero-divisor graph $gamma_i(r)$of a commutative ring $r$.

We discuss various properties of a ring over which each simple module is Σ-injective. We shall consider associative rings with identity. Our modules will be unital right modules unless stated otherwise. The class of right V rings was introduced by Villamayor [20]. A ring R is called a right V ring if each simple right Rmodule is injective. It is a well-known unpublished result due to Kaplansky ...

C . C . V a n d e S a n d e u n d F . V a n G a e v e r L a b o r a t o r y for Organic Mass Spec t rometry , State Univers i ty o f Gent , B e l g i u m Z . Natur forsch . 3 4 b , 495-501 (1979) ; e ingegangen a m 8. D e z e m b e r 1978 Chemical Ionizat ion, Carbocations, H y d r o c a r b o n s T h e invest igation o f several 1 3 carbon and deuter ium labelled n b u t y l a n d n -penty l b...

In this article all rings are commutative with unit, all modules are unitary. Given a ring A, its multiplicative group of units (i.e. invertible elements) is denoted by A*. The customary definition of a Euclidean ring is that it is a domain A together with a map F : A + N (the nonnegative integers) such that (1) I : p(a) for a, b E r3 (0); (2) given a, b E -‘-I, b m;’ 0, there exist q and Y in ...