uble or triple bond to any</span>
<span class="sd">            heteroatom</span>
<span class="sd">            - atoms in nonaromatic carbonâ€“carbon double or triple bonds</span>
<span class="sd">            - acetal carbons, i.e. sp3 carbons connected to two or more oxygens,</span>
<span class="sd">            nitrogens or sulfurs; these O, N or S atoms must have only single bonds</span>
<span class="sd">            - all atoms in oxirane, aziridine and thiirane rings&quot;</span>

<span class="sd">  