Question

Using Newman's casting patterns and taking into account the rotation around the C2-C3 binding, draw all the conformations alternating and opposite for:
(a) butane
b. 2-methylbutane c. 2,3-dimethylbutane
For butane, indicate the anti-periplanar, anticlinical, synclinical and synperiplanar conformation. For 2,3-dimethylbutane, indicate the conformation in which the maximum number of methyl groups is in the anti-periplanar position and the conformation in which the maximum number of methyl groups is in the synperiplanar position.

Answer 1

But ane и CH3 -с -- CHz New mann conformations СН3 • Front carben О-ack Cat: 4 СИ сы, Н 4 60 60° СН3 - А Н Anti (staggered) Antiperi planer н'C+3 к Antidinical t "synclinical + Go ↑ 68 Rotate back carron be 6° СН3 CHz сну СН3 см 1 боо Ж. HH во ни + Н н Anticlinical Н Syniclinical syn-periplaner - смо СН3 b) 2-methyl Butane: СН3 – с — и C# 2 сыз СН3 Сн “Н 3 65, Сн, боо - СН3 ctyl Н. зон, Н H н 1 synperi planer Н Н Synclinical 60 СН3 CHъ CH3 СН3 М. HHH 60° mos Н Н СН3 Antiperiplaner + сні Anticlinical

ро CH3 HC CH3 CH3 1 Etz 60° -CH3 H. и HE 68 바 H It CH3 H CH3 CH₂ Synclinical CH3 jooo 2,3-dimethyl Butane syn-periplaner (max methyl groups in sen Peri planer) CH3 CH3 Lowon CH3 600 • Chi •CH3 HA 법 ooc It * H (Hz -CH3 H CH3 Hea CH₃. It syn-periplaner CH3 T maximum Anti clinical CH3> Antiperiplaner

additional i just representing saw horse also

CH H H 60 HHH 260 H CH3 Ctz CH3 CHz CH₃ syn-periplanar (syn-Coplanan) syn-clinal Antu-clinal 60 CH3 H CH3 # H H H H 2600 # H CH₂ CH3 CH₂ CH₃ Anti-clinch Antu-periplanar (Anti-coplanar) syn-Clinel.

CHI Hн H H YYYY CH₃ CH3 Antu-clinal CH₃ syn-periplanar (syn-toplanar) CHz syn-clinal 60° CH3 Н. CH3 H H H H H GoG "CH3 H CH₃ CH3 CH₃ Antu-periplanar (Anti-coplanar) Anti-clined syn-clined.