Deliberate and emergent strategies may be conceived as two ends of a continuum along which real‐world strategies lie. This paper seeks to develop this notion, and some basic issues related to strategic choice, by elaborating along this continuum various types of strategies uncovered in research. These include strategies labelled planned, entrepreneurial, ideological, umbrella, process, unconnected, consensus and imposed.

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This study tracks the strategies of a retail chain over sixty years of its history to show how that vague concept called strategy can be operationalized and to draw conclusions about strategy formation in the entrepreneurial firm that grows large and formalizes its structure. The conclusions focus on patterns of strategic change and on contrasting characteristics of entrepreneurship and planning.

This study tracks the strategies of a retail chain over sixty years of its history to show how that vague concept called strategy can be operationalized and to draw conclusions about strategy formation in the entrepreneurialfirm that grows large and formalizes its structure. The conclusions focus on patterns of strategic change and on contrasting characteristics of entrepreneurship and planning.

A series of 8-(substituted phenyl) derivatives of theophylline and other 1,3-dialkylxanthines were evaluated for potency and selectivity as antagonists at A1- and A2-adenosine receptors in brain tissue. Theophylline has a similar potency (Ki = 14 microM) at both A1 and A2 receptors. 8-Phenyltheophylline is 25-35-fold more potent as an adenosine receptor antagonist than theophylline, while 8-phenylcaffeine is only 2-3-fold more potent than caffeine. A p-hydroxyaryl substituent enhances the potency of 8-phenyltheophylline as an adenosine antagonist. p-Carboxy- and p-sulfoaryl substituents reduce potency of 8-phenyltheophylline, yielding water-soluble adenosine antagonists, which are some 2-5-fold more potent than theophylline at adenosine receptors. None of the 8-(substituted phenyl)theophyllines are particularly selective as antagonists toward A1- and A2-adenosine receptors. 1,3-Dipropyl-8-phenylxanthine represents a potent and somewhat selective A1-receptor antagonist about 23-fold more potent at A1 receptors than at A2 receptors. A p-hydroxyaryl substituent further enhances potency of the 1,3-dipropyl-8-phenylxanthine at both A1 and A2 receptors. The 8-(2-amino-4-chlorophenyl)-1,3-dipropylxanthine is a very potent and selective antagonist for A1 receptors, being nearly 400-fold more potent at A1 than at A2 receptors. The water-soluble 8-(p-sulfophenyl)- and 8-(p-carboxyphenyl)-1,3-propylxanthines no longer exhibit marked selectivity. Both compounds are much more potent as adenosine antagonists than theophylline. The striking selectivity of 1-isoamyl-3-isobutylxanthine as an A1 antagonist is retained in the 8-phenyl derivative but is virtually lost in the 8-p-sulfophenyl derivative.

The structures and absolute configuration of two unique alkaloids isolated from the Colombian frog, Dendrobates histrionicus, have been elucidated by Roent-gen-ray (x-ray) crystallography. Histrionicotoxin is (2pll, 6S, 7pS, 8aS)-7-(cis-l-buteni-3-ynyl)-8-h-ydroxy-2-(cis-2-petiteni-4-ynlyl)-1-azaspiro[5.5] undecane, while in dihydroisohistrionicotoxin the acetylenic 2-pentenynyl side chain is replaced by an allenic 2-(3,4 pentadienyl) substituent. Dendrobates histrionicus exhibits remarkable interpopulational variations in amounts and composition of skin toxins, in behavior, and in phenotypic characters, aspects of which are illustrated in a color plate. The histrionicotoxins are the third class of alkaloids isolated from the defensive skin secretions of Neotropical (Dendrobatidae) frogs.

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