import re
s = '{qcos\\theta_{g}\\over r})^{2\\over 1 + \\alpha^{2}}}\\ 1234'
print( ' '.join(re.findall(r'\\[a-zA-Z]*|\S', s)) )
#Expect: { q c o s \theta _ { g } \over r } ) ^ { 2 \over 1 + \alpha ^ { 2 } } } \ 1 2 3 4'
#Obtained:{ q c o s \theta _ { g } \over r } ) ^ { 2 \over 1 + \alpha ^ { 2 } } } \ 1 2 3 4
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