Is there any difference between 'by the end of November' and 'by end of November'? I have looked 'end' up in the BBI Combinatory Dictionary of English, but it gives only 'by the end of the year" without further comments. I ask because I have a feeling that 'by the end' is used about the past (e.g. I managed to get it done by the end of August) and 'by end of' about the future (e.g. the report must be handed in by end of November). But is that true? Or can both be used interchangeably? Or is only 'by the end of' (formally) correct?
You should use "by the end of November"
The most common exception relates to plural and uncountable nouns. When a noun refers to a general concept or an unspecified quantity then the determiner is usually omitted. Wikipedia gives the examples
happiness is contagious
there are cats in the kitchen
However, in our case, end is singular and requires an article. Thus we should write
by the end of November
Not only is the correct choice grammatically, but it reflect the common usage. Using Google Ngrams we see that "the" is included in this phrase over 200 times more frequently than it is omitted. This reflects a strong consensus that that article is required.
But "end of November" does mean something
Consider the following OED entry:
end, (n) 7c: in attributive uses of phrases, as end-account, end-August, end-year (also followed by a specified year-date); end-of-December, end-of-season, end-of-term (also end-of-termy adj.), end-of-the-century, end-of-the-year.
Note these phrases act as adjectives (unlike your example where the end of November was the object of a preposition), even when the hyphens are excluded. For example, we might say "there are end of November sales at the mall", in which case "end of November" (or "end-of-November") is an adjective modifying "sales".
I do not share your feeling that excluding the article connotes a future event. I do not see any examples of this in the OED entry or elsewhere.